Bob: You're going to have a ball with that 38 Super. Just as Hammerhead said, modern 38 supers are headspaced on the case mouth and althoughhe suggests the use of 38 Super brass I have found that miniscule rim to be of no use whatsoever.
I have a Bar-Sto barrel in addition to the Colt Series 70 upper I use when i swap slides on my Springfield to shoot the 38 super. I have used stock 38 Super brass and 9mm Magnum brass cut to length. I have shot Winchester 9x23mm, Winchester 38 Super ammo and have interspersed 9x23 and 38 Super in the same magazine without any problems what so ever.
The last time I ordered brass I ordered the 9x23 as it is thicker at the base and does not bulge under heavy loads. Some of my older 38 Super brass, which has been reloaded numerous times, should probably be canned but that's tough for reloaders to do, as you know.....
Fun and plinking loads can be pulled right from the older Lymna manuals - you can use 158 gn round nose for a lot. I believe Competetion Bullets, if they are still in business, makes 160 gn round nose in .355, .356 and .357 diameters. Some 38 Sueprs come with 38 caliber barrels, some with 9mm barrels. You may wish to slug your barrel to determine its actual diameter.
Personal defense and smallish game loads can use a 115-125 gn hp at anywhere from 1400-1500'/sec. I once took a south American Jaguar using a Charles Askins load of a 115 gn hp and H110 powder, and it worked. I also used that load, numerous times, on Javelina in both South America and Texas.
With proper tuning your 38 Super should be able to feed semi-wadcutters and then you would indeed have something very close to your 357 magnum semi-auto. It's one of my favorites. Mikey.