>>53104120I've done this myself as well, but with all the Champsions.
Here were the first 3 Gens.
Red vs. Blue (4-3/Red)
Red vs. Lance (5-2/Red)
Red vs. Steven (3-4/Steven)
Blue vs. Lance (3-4/Lance)
Blue vs. Steven (4-3/Blue)
Lance vs. Steven (7-0/Lance)
Overalls
Lance (13-8)
Red (12-9)
Blue (10-11)
Steven (7-14)
Note: This is with perfect evs/ivs, their own movesets, and all Lv. 100. It'd be different with actual different levels however. Blue is also hard because of his starter and team differences (which I excluded the starters). So take that as you will.