Very good questions Jeremiah.
And let me say that your Avatar is interesting... I hope that the chimp isn't smoking banana peels in that pipe... :D
First there are any number of opinions on the subject of pipe resting and when it should be done. I think the answer is one of personal preference. Some say as you indicated that 1 bowl and rest. I for one will smoke a pipe all day, and quite often for a number of days in a row before resting it... The pipe will change its characteristic smoke when it's ready for a rest. Some pipes require that no more than two bowls while others can go a week. It all depends... But, when I do rest a pipe it can be weeks before I pick it up again and I will always give it a good cleaning and attend to the cake before smoking it again. That's the way I do it. Smoking and resting is a very individual thing based on one's preferences. You'll grow into your own method/cycle... IMHO (In My Humble Opinion)
The second question is about "dottle". You will find that different tobaccos will leave different things in the bowl... Some will be nothing but white ash (e.g.SG Grousemoor). Some will leave dark ash and some dottle (e.g. Sasieni Balkan), and some will leave a gooey clump of unburned tobacco (a lot of different tobaccos). Packing can have a profound effect on the remnants, as well and the rapidity of puffs... there are any number of factors. I wouldn't think you are doing anything wrong in particular. Nothing that slowing down, and practicing won't cure.
Side Note: There has been some discussion lately about dottle. I for one and a few others here will dry the dottle and smoke it, as an early morning or late evening smoke with some hearty black coffee. Others would rather be poked in the eye with a sharp stick. The choice is entirely up to you. But, that is the nature of pipe smokers... we're all individualist to some degree, otherwise we wouldn't march to our slightly different cadence.
