Whyzee.
In response to your questions. I live in South Florida, and it has been fairly low humidity and cool (70's), but it has also been very clear with almost no cloud cover.
As for my vendor, he buys GT104 in 55 gallon drums direct from Sunoco in PA. then pours out eleven cans and seals them with the knock out cap and screw on cap. So the fuel isn't stored in tanks. Both the rep at Sunoco and the local dealer had the same story about the five gallon cans because I had suggested to the rep how it was a factory sealed can and he mentioned they only sell in 55's to my dealer.
The fuel numbers are quite similar and this was one reason for trying the GT104. For me to buy C-12 the vendor pumps it. If you want a five gallon can they fill it from the pump and close the lid. I haven't been down to Fort Lauderdale to see but I think they store below ground.
As for pricing, I was quoted $4.50 per gallon on C-12, the Sunoco GT100 and GT plus are just under $31.00 for the five gallon can.
After giving your previous post some thought, I think another factor to letting the UV into the YZ's tank is the fact I run no graphics at all on the tank, this can't help.
I am curious to see what your fuel did. I've gone back to pump fuel trying to flush the remaining crud from my tank. I rode a while yesterday and didn't plug the pilot jet, but there was trash when I drained the carb and pulled the main jet cap. I've never had any issues working with the YZF but at this point I could likely apply as a teh rep for Kei-Hin.
Thanks
PK