Yes, I agree, purist short twin keeled set-ups do quite well with the fins at or near the split.
Here is a comparison of very different approaches to fin set-ups:
The board in the foreground is a bigger fish. Back in the day we called them “Whale fish” as long as 9’6". I’ve seen Stevie with fish set-ups even longer before going to 5-fin variations. The board above is 7’6" so it is really a Pygmy Whale. Fin position is distorted by my bad habit of using a fisheye (sorry). They are not up as far as it looks.
The keels are up because of length- locations took a lot of testing, cutting off, re-glassing, but in general, the longer the fish gets, the more they seem to benefit from having the fins: up forward, taller in profile, and being toed-in slightly.
Semi-keels are up about 7-3/4" on this one, as the hull length allows for more rail to do the work plus the rider is (should be) up forward more on this length/design. This keeps the sweet spot just ahead of the fins where the rider should be most of the time. If the rider is too far back on the board, then the tail is too wide for the given design and the fins will overload.
The taller fins are a function of reducing the fin base length. These 6-1/4"L x 5-3/4"H semi-keels have less base to take some of the drive out of them (the rail is taking this task on a bit due to hull length). As the bases get smaller, the fin area needs to stay useable, so the keels get deeper.
Toe-in comes into play with more length, kind of like the rear-steering on a “hook and ladder” fire truck. The rear end is allowed to translate side-to-side a bit more to get the longer hull around in a balanced amount of time for the overall bulk of the board. Toe also keeps the fins from loading up too much and too quickly at lower speeds.
The board in the back of the photo is more traditional, 5’8" and with 11" tails and 5-1/2" split. The 8-1/2" x 5" keels are up around 6". As a note, these particular fins do not line up with the tips, but are actually measured 1" in from the rail edge at the rear of the fin. They are outboard of the tips and parallel with the stringer.