Never used the scavenger myself , and I am anal about my oil . My Ultra with oil cooler takes almost 4 qts , which leaves not much , more or less in the bike ..
In my experience , if you change when you are supposed to change oil , wont be an issue . I get an Oil Analysis done at every oil change , and these TC's run really clean anyways ..
As for using dino oil , with the heat generated by the TC , I think , syn is the way to go , tho there are peeps who use dino in the TC
So Many Highways So Little Time