re: BK said, in today’s PC, that we’re gonna to see Maason play more 3 and 5 technique

Alignment of a defensive front. Generally, a 3 technique lines up outside the guard, and a 5 lines up outside the tackle. (Even numbers generally indicate "head up". E.g., a DT who's head up on the guard is a 2.)

I think what this is about is getting Jordan Jefferson on the field more, which I think is a good idea. But the defensive staff seems to have issues figuring out personnel, and the best positions and rotation for personnel.