Ziplock Mylar/Aluminum Foil Ziplock bag performance test

I recently shared a photo of my short- to medium-term tobacco storage solution which uses 5 mil aluminum foil and mylar ziplock bags. Upon opening a 50g tin, I transfer the remaining tobacco to these bags. These store neatly in a shoebox-shaped tray. This is not only compact, but makes finding the tobacco quick and easy. This system has worked splendidly for me for the 9-months or so that I've been using the system. That said, the majority of these bags are kept in either my humidified locker at the cigar store or my floor-standing, metal-lined Dunhill humidor, so those bags all have a extra layer of protecting against dehydration. I keep some aromatics in an open tray in my basement utility room as well. I haven't noticed any loss of moisture in any of these.
Predictably and understandably, my post resulted in cries that only glass jars are sufficient for tobacco storage. Another suggested that heat sealing was necessary. There is likely truth in all of these concerns, but I wanted to determine conclusively not just for myself, but also for the pipe community whether these bags were sufficient for say, three years of storage. That's my goal for these -- three years. For most pipe smokers, I think that's a more than reasonable amount of time to finish an open 50g tin.
Here's my methodology for the test. I am using Peter Stokkebye Proper English as the test tobacco. It came from a single glass 1-1/2 pint jar that I cellared about a year ago. The hydration of that tobacco should be very consistent. In addition, since I believe it lacks casing, it is likely to give up moisture faster than an aromatic, for instance. 20.0 grams of this tobacco were placed in 5 layer 5.0 Mil PET Aluminum foil mylar bag with only a zip closure and an identical quantity was placed in a new, wide-mouth 1/2 pt glass Ball jar with a brand new lid. This resulted in a modestly packed jar and a bag which is filled to less than half of its capacity. This should be a handicap for the bag, but I wanted to test an average amount of tobacco, so I chose around half a tin, since tobacco will be removed over time in normal use. The weight was tested and retested on a highly accurate Acaia scale which is accurate to 1/10th of a gram. To put this in perspective, 1/10th of a gram is the weight of two drops of water. In addition, I have a brass 20g control, to verify the scale's continued accuracy. These bags will be stored in an upstairs bedroom cabinet.
I will update this thread periodically over the next three years with the results.
Hopefully, this scientific approach will provide reliable information on whether or not these bags are a viable solution for short- to medium-term storage. Since I have no thought of using these for cellaring, I am choosing not to test heat-sealing them.
Here's what the system looks like, with a Dunhill tin shown to provide a size perspective.

Regarding controlling the humidity levels, I'm not concerned about that since I am attempting to evaluate effectiveness in normal use, without humidity control. I can say that in my home, tobacco stored in standard pipe tobacco humidors, crystal biscuit jars, and the like will all dry unacceptably within six months. If the bags aren't effective, my home's environment is dry enough to expose it.
The point about the seal being the weak point is valid, however I have had no mechanical difficulties or failures so far with the bags I am using. The issue of tobacco bits fouling the integrity of the Ziplock is also valid and it is something you do need to be vigilant about. That said, you can encounter similar problems with canning jars lids. The biggest danger is when the bags are very full, as it makes closure more difficult. I wish these bags were gusseted.

I'll mention, too, that these bags are great for throwing in a bag when you're packing your pipes to smoke elsewhere. Much lighter and more compact than jars. It's difficult to load a bowl from the bags, though, so I always dump some tobacco on a leather mat that I keep in my pipe bag.

I think I've seen that photo before, or a similar one, Woods. It's an excellent idea, too. Between the tin and the Mylar, it seems pretty safe. I don't think the clear bags are quite as effective as the foil-laminated ones, but plenty good enough when the tobacco is inside a tin. No "ghosting" the bag, either! However, I was also looking to reduce space, hence my compromise.

As promised, here is my first set of findings after six months.
As a review, I stored 20g of Peter Stokkebye Proper English in both a 4oz glass canning jar with a new lid and a 5"x5" mylar/aluminum ziplock bag. My assumption was that the starting moisture by weight (MBW) was 17%.
I also had a piece of brass hardware that happened to weigh 20g, which I used as a control. This has turned out to be important, because my scale needed repair after it bricked during a firmware upgrade. When it came back from the manufacturer recalibrated, I'd lost .1g off the weight of my control, which now weighs 19.9g. Therefore, I've adjusted downward the original weights by .1g.
Jar:

Weight loss: 0.2g

Percentage of original moisture lost: 5.91%
Mylar/Aluminum bag, ziplock seal:

Weight loss: 0.3g

Percentage of original moisture lost: 8.87%
My early assessment is that both the mylar bag and the jar lost more moisture than I had expected; but on a relative basis, I'd say that they performed about as expected. The jar was definitely superior to the bag. My minimum level of acceptable MBW is 12%, which means that the total weight can drop by 1.0g until it becomes too dry for my taste. At the current rate, the bag will reach this minimum level in 1-1/2 years. The jar will take 2-1/2 years. Will this rate of loss continue? Somehow it doesn't seem probable that the jar could continue losing moisture that quickly. At such low weights, the scale's rounding can have a profound effect. I'll revisit this in six months.
I am satisfied, however, that for short to mid-term storage, the mylar bag is proving to be adequate. Issues that occur to me are:
- Would the results be different for tobaccos with more humectants? Of course, we don't really know how much, if any, is used for Proper English, but my sense is that it isn't much.
- How would jars hold up versus the mylar bags as you smoke through the tobacco? Over time, the jar's air volume would increase, while the bag's should increase little, if any, since you can evacuate much of the air. Could it be that the jar wins early and the bag wins late?