I had a .36 Le Page and it would shoot far better than me! I used Swiss 1 (11 grains) with a cast round ball (.352") and a 015" x 1" patch. I adjusted the rear sight for a 6 o clock aiming point (balancing the black) and it grouped very well, best I shot which was coincidentally the first time I used it was 96/100.
The load remained the same for the majority of time I owned it, the only variation was a thinner patch (012") but it didn't make a significant difference. I've since gravitated to under hammers but my eye-sight hasn't gravitated with me!!