With the Knight about any black or "replica" powder will work fine. I called Knight when I tried T-7 and they told me it would handle up to 120 grains behind the 2 1/2 oz of shot.
I found 120 grains of T-7 was too much for getting good patterns, and way too much for keeping my IQ at it's present level.
100 grains of T-7 ffg, 120 grains of Pyrodex R/S,or 120 grains of Goex ffg all worked well for me.