165gn is a great bullet weight for .40S&W, but it has not received a lot of attention. I find that 145gn bullets are even better in my guns, and that weight is also quite neglected.
Then, add in the fact that "most" manuals are trying to cover all the new powders, and old powders like Unique tend to be ignored.
Here is a summary of the few loads I have compiled from various reloading manuals:
Bullet Weight Powder Weight Velocity Note P.F. COL
Berry's P-FP 165 Unique 6.0 1020 168 1.135
Spr TMJ 165 Unique 5.4 952 Start 157
Spr TMJ 165 Unique 6.0 1034 Max 171
Spr TMJ-FN/GDHP 165 Unique 6.2 882 Start 146
Spr GD TMJ/GDHP 165 Unique 6.2 882 146
Sierra-JHP 165 Unique 6.5 Start 0
Spr GDHP 165 Unique 7.2 1064 Max 176 1.120
I would start at 4.8gn and work up to 6.0gn, watching for pressure signs. Note the fact that one source found 6.0gn to be a max load for jacketed bullets in their gun using their components, so approach 6.0gn with all normal caution. The fact that the source shows a velocity of 1034fps indicates that they were achieving peak pressure.
I would probably be satisfied at about 5.5gn if accuracy is good and the gun functions.
If you ever decide to try another powder, I find that AA5 is fantastically accurate with almost all bullets in .40S&W (but don't try to push up to MAX loads) and Silhouette, at closer to MAX pressure is almost as good. 231/HP38 is also a well-behaved powder with .40.
Be sure to check your loads for bullet pull, as the .40 is even more temperamental about bullet set-back then the 9x19. I don't think there is another cartridge out there that KBs as easily as the .40.