I have found through the years that w231 and Alliant Green Dot are very close in fps and pressures.

If you notice, Bullseye's maximum is listed at 6.1grs with that bullet.
Since GrDot and W231 are a little slower burning than Alliant Bullseye powder.....................

I would think that working up to 5.8 grs would not cause a problem but...............

Unique or 2400 would be a good choice if you don't mind using MORE powder.