I think what
Dottie says about becoming a pipe smoker first before considering being a tobacco blender (mixer actually) is actually quite important. Once you have several months smoking behind you, hopefully of differing blends, then you will have a much better idea of what a specific tobacco contributes what particular flavour to a blend.
I would also suggest going the weigh scale route over the tablespoon route as it is more precise and therefore more easily repeated for consistency. Also always keep notes of what has gone into your concoctions.
I think it was
Crash who suggested leaving your 'mix' a while. This allows all the flavours to meld. As little as possible air in the mix is also preferable.
I have been doing this mixing thing for a few weeks, only in small quantities, 10g of this, 15g of that etc and I use small zip-lock style bags for my 'creations'. I squeeze out as much air as I can afore closing the bag. It is then rolled up with a rubber band, labelled and placed in a plastic Tupperware type box. They will stay there for at least a month and I look forward to spending a day just sampling my mixes.
I say go for it, it's hardly rocket science but then it's not true 'blending' either :
:
Regards,
Jay.