Just picked up a Henry in 360 Buckhammer. Planning on getting the Lee copy of the RCBS 200 gr. RNFP for hunting loads and using 158 gr. pistol boolits for target/plinking loads. There is some data from Hodgdon here: https://1895gunner.com/loaddata/table%20360BH.html
Looks like 1680 and CFE BLK are the top choices for this caliber with some Lil' Gun and 4227 loads as well. I don't have any of those (I might have less than a half pound of some 4227 and Lil' Gun) but I do have several pounds of H4198 and Reloader 7, which are pretty close to the 1680 and CFE BLK.
It seems to me that the 360 case capicity would be very close to the 357 Herrett. I see 357 Herrett data in several loading manuals (Sierra, Hornady, IMR) that I have with these three powders. The one powder that I see data in both calibers is 4227. With 180 and 200 gr. bullets the data shows about 3 grains more for the 360 for both starting and max. loads.
Would it make sense to use the Herrett data as a starting point for 360 loads with the H4198, Reloader 7?