Ok...job done
It turned out that I could only get 400 grit, 600 grit and a 220 grit for awkward marks etc. However I bought a buffing wheel along with two types of pastes...one for pre polish and one for final.
Like you I found that I had to go to the 220 grit to get off what I think is some kind of cerakote and as you said a little bit of work was needed to get the edges clean because of the rounded profile on the Drag 2.....Pic below....love it
The pictures don't do it justice though in reality its like a high gloss mirror finish....super super shiny. I'd recommend the process to any one.