As i am in an isolated part of the uk where getting suitable oil is always a bit of a challenge i use anything i can get that is suitable for a sportster transmission i think i currently have a wee stock of formula+ but have used in the past sport trans fluid and a few others
As far as powdercoating your engine - my vote is for wrinkle black. Pain to clean (sometimes), but nice look for motor. Mine will be going in for some poder work after the holidays...
I have used Amzoil top and bottom, in my 77 Sportster since my rebuild in 89. In the beginning I believe I started with 60 weight. I use 20W-50 now but at the time I ask all the mechanics because synthetic was so new, not one would commit, so I went for it. Since I know nothing about the new bikes I just want to say Amzoil has done alright by me. They are very proud of it though.