In the Hodgdon No. 26 loading manual, "HS-6" is listed with data for various bullet weights in .44 Special. Should you now have access to that work, I found at least one website (do a search) listing that powder for that cartridge.
Hs-6 is not a 'slow' burning pistol powder, more the 'moderate' range, so performance will not equal that of 2400 or 296 or H-110; more like Unique or Power Pistol I should think. However, HS-6 requires specific data, and substituting charge weights of another type powder should not be tried. Based on the information in your initial post this should enable you to load and shoot without purchasing any more powder (should you find any).