Another vote for the RCBS 98gr SWC in the .32 Magnum. I have a Ruger Super Single-Six like yours, but with the 6-1/2" barrel. It loves the RCBS for moderate loads (up to factory pressures).
For heavier loads (above .32 Magnum factory pressures) I use the Hornady 85gr XTP. I took the Ruger up to 8.0gr of 2400, but had a little problem with ejecting them through the narrow ejection cutout. Too much drag. I polished the insides of the chambers with 1000 and 1500 sandpaper and reduced the load to 7.5gr and have no problems with ejection any more. I would not use this load in anything other than a Ruger, but have had no problems since polishing.
Like 9.3x62AL, my .32 Magnums prefer the lighter bullets (85 to 100gr) and my 32-20s prefer heavier bullets (100 to 120gr).