Hey, hello, Tom
I'm running the Halcyon 830, round, mirrors on stock bars. It looks like the 820 has a little different attach fitting though. If you're interested in changing the bars then the fit up will most likely be no issue. Keeping the stock bars I just used a belt sander to reduce the diameter of the fittings enough to slide into the stock threaded end bars. If I had some other machinist capability I'd have gone down that road but I just used what I had. Made it work.
Recommendation? It's your ride, make it what you want.
Plenty of riders have swapped out GRiSO bars so they'll be along shortly I'm sure.