I've used the Kreem stuff to good effect. I think it's real important to let it dry and cure long enough before putting any gas back in the tank.
Also after both the acid treatment and the acetone solution wash, it's a good idea to hang the tank for a day or two with low pressure compressed air blowing through it - really helps drying it out properly. If it's not clean/dry, the coating will not stick properly and peel off causing nightmares.
I'm also interested to see what that POR-15 looks and feels like once in and cured. The tank I just put in my Max (from the spare bike) had a coating that looked like some kind of silver very hard paint, I've never seen anything like it before.
Today I replaced the glass fuel filter with an OEM one, and was pretty horrified to see the amount of crap the pump already managed to suck out of that tank, and I thought I'd got it pretty clean! Anyway the bike's running great still, so at least I know the filter did its job properly..