I agree it would be difficult to get physics level accuracy in the home without some precision instruments... In the grand scheme of things, through process of elimination and some experimentation, one can find the most optimal blend for a given scenario by collecting some simple data.

Do you have a lab to test the accuracy of your fuel blending to find the optimal blend, or do you just find what works best and use it? I mean, we are dealing with micro sized 2-4hp engines, not 2000hp top fuel dragsters. At what point do we get too pedantic with a subject such as this? Not trying to fling poo or start a keyboard war. Far from it actually - I would hope by now you know I’m not like that and have a lot of respect for your level of knowledge.