I did the Kreem process on a CB550 tank about 7 years ago. Cleaned, rinsed, dried, and coated an already painted tank. I fan forced air into the tank to thoroughly dry the coating (about 2 weeks). Over the years the coating turned from the as new cream color to a grey brown. However, there was no peeling, scaling, or deterioration I could find when I sold the bike a month ago. There were also no particles in the carb bowls either when I drained them to check for debris. I only use the in-tank filter (75 model).
I don't think you can do a good Kreem job in one or two days. And I expect many who have tried just that determined the Kreem process "crap" when it failed later. Any paint system can fail when the prep work is shody.
"Tis a poor musician who blames his instrument for a wrong note played".
Cheers,