TL;DR: How to cut wide, deep rabbet in hard maple without exhausting myself?

I have a bunch of rabbets to cut in some 7' long curly, rock maple boards. This is for an interior trim project and I need to fit them around some framing lumber in the archway into my den.

The boards are about 7/8" thick and I need to hog out most of the depth leaving about 1/4" of material left. They need to be about 1-3/8" wide. So a decent amount to remove.

I did the initial shoulder cut on the slider, but the board was twisted just enough (wind I cant do much about) that the TS technique seemed not that safe or accurate.

Normally the answer to this would be my veritas RH skew rabbet plane, but the grain was going so hard the other way it seemed to make me question if this was really the best idea. I did that enough to get down to a bit of a lip on the sidewall, then switched to using my LN 10 -1/4 left handed which seemed to work better but was much slower then I really wanted. I think adjusting the mouth wider would help. I was getting a lot of jamming in the mouth, so I think that may have been part of my problem.

Do I need to just pony up and buy a matching LH Skew Rabbet?