looked like a RIC copy to me...but the add is gone now...
the 11th edition of Cartridges of the World has info.
it lists a
.375 bullet(other sources say <> .360) and indicates 38 S&W and 38 Short Colt load data is appropriate.
this is the 38 S&W data from the same reference for the powders you have listed:
bullet............................powder..............grs...............velocity................energy....................source
148 lead.......................Bullseye............2.5.................700....................161........................Speer
158 lead......................Unique...............3.0.................700.....................172......................Speer
I would start below these and work up to them, being very sure that the bullet has cleared the barrel before touching off a follow up.
The onus is on you to determine that your iron is safe to shoot, and all the other previously stated points.
I post this strictly to give you an idea of the published data available.
I used 2gr of Green Dot in my .380 with 125gr soft cast .360 bullets.
jethunter has bullets available if it slugs in the .360 range as mine did:
http://www.canadiangunnutz.com/forum/showthread.php/879482-Antique-Pistol-Bullets
Good luck, have fun, be safe.