VV shared with me a recommendation of 3.0 to 3.4 gr. N310 (start thru max) for a 122 gr. bullet. That's prolly close enough for a 124 gr. projectile. I loaded some 122, 125, 115, and 147 over N310 and the results were generally outstanding. In all cases, the rounds are very soft shooting. At the low end a pistol with standard springs won't cycle. Many of the loads showed great accuracy potential. I got to 3.5 gr. of N310 under a 125 gr. rnl and just nicely made minor (PF for IDPA or IPSC). I think you have to work up your loads for your particular needs in your gun, watching for the usual signs. All usual disclaimers apply. The "published" data seem to be very conservative but you must exercise caution when stepping out of bounds.
Nevertheless, IMHO, the results with this powder more than justify the time taken to work up a load.