The Lyman 49th Ed. shows 6.7 - 7.5 gr. of Unique behind a 200 gr. Hornady HP/XTP #44100. They used a 4" and a 7-1/2" pressure barrel, but don't specify which the data came from for this load. The 7.5 gr Unique chronographed at 854 ft/sec with 11,300 CUP, the lowest pressure for any of the powders shown. However, I suspect a 2-in. barrel will exhibit a lot of flash with Unique. You might want to try HP38/W231 (same powder, different label), which is faster-burning. They show 6.4 gr on the low end, and a max of 7.1 gr. at 13,800 CUP with the same bullet. For cast bullet data, you might want to pick up a copy of the Lyman manual, as there is a lot of data for me to copy here.
[I can assume NO liability for the use of this data in any guns at all! Usual disclaimer.]