My avatar is a crop from an 8x10 negative, and the crop is about 1/2 the size of a Minox frame. If you want film grain, then you have to make a significant enlargement to see it. You can use Ilford Delta 3200 in a 6x12 roll film back. The grain is awesome! You can push a grainy film in a "grainy" developer. Perhaps Tri-X or HP-5 in Rodinal would be a solution, here. You could also try Arista Lith film, too.

LF doesn't lend itself to grainy photographs very well.