Guy B. Meredith said:
1. Reloads. .38 spl 158 gr at about 900 fps
Do you know the accuracy potential of these reloads...how tight
will they group?
I recommend that you start with 148gr target wadcutters that you know will group. You can go back to your load of choice after you get the gun sighted in.
2. I am trying to sight in at 25 yd. Is this correct for sighting in expecting to do most shooting under 25 yd, but some out to 50 yd for an ICORE standard stage?
You're starting too far out. Much like a 5.56x45mm rifle which you'd sight in at 25m before moving out to 200m, you need to get it into a group first.
I recommend you start out at 7-10 yards. At that distance, all your holes on target should touch. From there you can adjust your POI to where you want before moving back to your desired distance. I'd personally check zero at 15, 20, and 25 yards before moving to 50 yards
3. Standard S&W adjustable sights, front centered between and top level with back. Top of front set for impact point.
If you have the white outline around the rear notch, I'd paint it black
4. Shoot N See previously, but will be going to commercial sighting in targets.
You don't say which size your Shoot-n-See is, but the 1"-2" ones are very good. I can also recommend shooting at a brightly colored 2" square rotated 45 degrees, so it looks like a diamond. That would be at the further distances. When you start out (7-10 yards) I'd shoot at a 1" square
5. I haven't had the bag out for a while, but I believe the trigger guard and hands to prevent burning the bag.
I'd put a bag under your wrists and another under the barrel. If you only have one bag, one under your wrist will offer a greater stability. Don't rest the butt of the gun on the bag.
The groups are not near tight, but do group. Maybe 8 to 12 inches at 20 yards offhand. Yes, they do move over the target with adjustment.
The rule of thumb is that you can't really make adjustments smaller than the group you can shoot.
Off a rest, you shouldn't have much trouble shooting a 2" group at 25 yards