hey there PsyDuckMonkey, these are great questions and i hope your experiments are going good.

there are two approaches in your first question, about using or not using aluminum foil inside the Jar, some people say aluminum is a must for them, i have also heard of people just using a layer of zeolite on the bottom of their jar and a layer of CBD above the zeolite, and when heat is applied the CBD will melt through the zeolite, personally i did not notice any difference being made on the final product between these two methods, in my humble opinion its a matter of personal choice, because remember, there is not much existent scientific literature on the subject for us to be certain of a method and know exactly how well it works, experimentation is our best friend in these cases, on the other questions, i do not believe the ethanol vapor (if any at all escapes the flame) will contribute by any means to the isomerization, now as you mentioned the burning of ethanol  will

create water and carbon dioxide, but here is the trick: this happens only in a oxygen containing environment (source: The science of alcohol)   ,now remember water needs oxygen to be formed and we have a flame in a sealed environment which will keep going for as long as there is sufficient oxygen inside  ,so there shouldn't be any significant amount of H2O created if any at all, i think you get the idea by now (also another flammable solvent can just as easily be used, just make sure its anhydrous if you want no H20 present of course), also the only reason water would be unwanted is if you wanted to minimize Δ8-THC being present in your product, other than that its nothing to be worried about, for example if someone wanted a purely Δ8 distillate he would use water as a medium and something like citric acid for a catalyst

as for the heat transmission this is a very good question since glass is the opposite of thermoconductive, this is why i said that you put the reactants in the oven at 105C and start your timer at 150C, i believe that this in-between period offers enough time for the heat to be distributed, however heat is the only factor i would suggest to everyone to experiment with himself, since different ovens etc. will probably have slightly different results (i mean there is probably difference in heat distribution etc. between a 10 year old cheap oven and a "smart" oven made at 2023), this is where the potassium hydroxide CBD reagent test can come in handy, you are able to test in real time conversion rates from your specific timeframes and equipment.

keep it safe and DYOR.