With radius arms there are no "angles" that will change. You don't have to worry about anti squat/anti dive etc until you go to a true 3 link setup.
As far as JJ's you can mount them anywhere you please. There's nothing that says you can't use them at the axle end AND the frame end. If your only using one pair then yes, put them at the frame end.
As said above, make a nice beefy Xmember then add mounts to it at the right length to tie in with your arms.
I'm running the same set up, mines a custom radius arm setup with one upper on the pass side and it works GREAT. No DW or other weird handling issues and I don't even use a steering stabilizer. (jj's at all 6 attachment points)