You are right! It's to long. I did another run or UN-54 at 10min with Rodinal 1:50 at 20 and it can be shorter to. So I'm getting closer to your time. My starting point was APX-100 and I run that film 12.5 or 13 min in Rodinal.
My last run was in Xtol 1:1 for 8min 20C and I'm very happy with results. Maybe I can cut it to 7min or less but also I would like to drop speed to 50 or 64 iso. Pictures are at:http://flic.kr/s/aHsjxscdGt
You can order film here:
UN-54 has pretty clear grey base. Sorry, no densitometer here to give you B+F value. I did BW reversal processing years ago with EFKE KB50 and ORWO reversal recipe 9home made) it was very nice film for it. I don't think I will run another reversal processing with this ORWO stock.