I tried T-7 in the .58 as well as the .69 as I had a couple pounds of it from a number of years ago. In the .58, it worked OK, but showed slightly poorer accuracy than the GOEX 2F I normally use with lighter 75gr. charges - at 50 yards. I didn't try it farther out. Fouling wasn't a problem, about the same as GOEX 2F - no buildup at all so it's hard to say which is better in that regard.
In the .69, T-7 was vastly inferior in accuracy, with wild shots, even at 50 yards, however there were no high pressure indications on the patches and all were reusable, as normal by merely re-lubing them. I found the T-7 to shoot roughly 3feet high and 3feet to the left at 100 meters off the bags, while the real BP shot into the target's centre as is normal with GOEX 2F. This, I found most interesting & subsequently stopped using T-7. Your rifle seems to respond to it quite well - guess that proves all guns are unto themselves and wil show us what they want. Note the roughly 200fps higher velocity with T-7 over GOEX or Swiss - higher pressure gives higher velocities.
I've read that in some guns, T-7 gives pressure excursions in heavy loads. I can bleieve it. I know of a couple guys who are using 175gr. T-7 in their 12 bore Pedersoli double rifles - something I'd not want to do with their gun designs.