I have used both 6 gr Unique and 7 gr Universal (which is very close to Unique's performance) to good effect.
Only way to know is to try it out
When trying a new combination, I usually load a box of 50 in a "ladder"
with 10 rounds each of like 6, 6.25, 6.5, 6.75, 7 grains powder, everything else the same.
Your gun will tell you which one is "magic" if you shoot off sandbags for groups.
Then you can chrono the good load and stick with it.
The snubbie target was offhand.
The target labeled #12 might have been, don't remember.
The 200GD target shows what you are looking for off sandbags.