The best I can do is:

Lyman lists 4.0 - 5.0 gr of Unique for rifles with 115 gr 3118 bullet (5.0 = 1380 fps)

For pistols, 4.5 gr Unique, 925 fps in a pistol

NRA lists, 4.3 gr Unique, 1200 fps, 26" bbl

Hodgdon 3.0 gr Titegroup, 15,000 psi, 850 fps in a pistol

ALL LOADS ARE USING A 115 gr LEAD BULLET.

I shoot a 180 gr bullet, breech seated in a HW. My loads are 9.0 gr, AA#9 and 10.2 gr 296.

I think for fixed ammo, if you reduce those loads 1.0 gr and use a 115 gr bullet, it should be plenty safe in a LW.

Frank

This is a very timely discussion for me. I just picked up a #2 Remington rolling block in 32-20. For a mild starting load I'm using 7.5gr of 2400 under a 115gr bullet, and 8gr under a 98gr bullet. 

I also found that using a drop tube and about 1/8" compression I can load 20gr of 2F Old eynsford under the 98gr RCBS bullet, which very closely replicates the original BP load.