I would not use atf. Atf has additives in it to prevent burning. I would reccomend 2 stroke oil over anything. VP44 pumps are very picky about lubricity as well, and believe it or not, atf is very grabby and does not lube as well as you would think. Lots of guys on other forums I'm on use the 2 stroke oil regularly to lubricate the pump. I use it on occasion, but I usually just fill up with straight #2 and don't worry about it. I also use Howes Meaner Power Kleaner about once a year. I was skeptical of it at first but after running 1 bottle through 2 tanks it cured my sticking injector issue when I still had my stock injectors.
Anyway, as a general rule I DO NOT reccomend atf as a fuel additive, mainly from a lubricity standpoint. Not to mention all the deposits it can leave behind due to the anti-ashing/burning compounds in it.