Sorry I'm not gonna be alot of help. Years ago I experimented with 405gr LFP bullets made for the 45-70 sized to .454" and shot in my H&R 45 Colt carbine. 5gr of Trail Boss helped the bullets clear my 20" barrel at about 400fps. I ran out of case space and wouldn't be able to get anywhere near 1000fps with that powder. These days I'd look at Unique, Red Dot, or maybe even Bullseye.
I don't have any SubX bullets in my Quickload library. If someone can provide the bullet length and COAL I could probably extrapolate the data.