Going Green.....

I am curious if you are using the stock fuel tank? Any concerns with evaporation if you are?
This is the big worry I have heard of......like alcohol , E85 will suck moisture out of the air.
I have a sumped stock tank that will be what I go with initially.
I am considering some kind of seal on the cap if the car has to sit for any length of time and I will drain it for long term. ( We have winters here )
It might be as simple as a baggie under the gas cap while it sits from Sunday eve. to Friday night.
One person with a lot of experience with it told me that storing it in plastic cans or jugs isn't the best either.
Sealed steel cans kept in a cool dry area is optimum.
Around here I am pretty sure I can find it on the way to either track I will run at , and if not , I guess I tote cans. But that is plan B.