I sat down to load a few trial shells swapping the SG28-II wad for the WinAAHS wad.
Not trying to be a smarta$$, but why
? Are you even sure you can safely swap those wads?
The problem is that the SG28-II is SIGNIFICANTLY shorter than the Win wad. What is the best way to fill the void?
First, I'd start with a recipe specific to that wad instead of doing a blind component swap. (I'm hoping that Ballistic Products has done my homework for me and has an appropriate wad column).
Try to find and use a recipe with a bulkier powder. Increase your shot drop slightly. Last resort: I've read posts with filler jury-rigs using dry beans, styrofoam, cardboard, felt, and overshot cards.