Just doing some musings, with a triangle calculator......
If the center of mass (CM) of the engine/transmission is 100" from the rear wheels (just to make the math easier, I know it's closer than that), and the suspension goes up 5" in the front and down 5" in the back, then the suspension "squat" effectively moves the CM back toward the rear wheels about an inch. The entire vehicle rotates about 5.7 degrees. That's because the CM moves in an arc, not because it gets physically closer to the rear wheels. The wheelbase is effectively an inch shorter, because of the rotation. That's a teeny bit more weight on the rear wheels, half a percent.
Making a ridiculous engine mount with the same 100" between the engine/transmission CM and rear axle, but with the driveshaft angle at 45 degrees, then the CM of the engine/transmission is now only 70.7 inches, horizontally, from the rear axle (but we have to raise the CM of the engine/transmission 70.7 inches to do that). What happens when the suspension 'squats'? The car rotates the same 5.7 degrees or so, but the CM of the engine/transmission is now just 63.3 inches from the rear wheels. So there's about 10% more weight transfer, of the engine/transmission, because the engine started out 6 feet up in the air.
But that's just the weight transfer from the engine / transmission, not the entire vehicle. So yeah we got 10% more weight (of the engine/transmission) on the rear wheels..... but we have to put the engine 6 feet higher!
So going up or down an inch isn't going to mean 'squat', no pun intended, in the real world. People can fool themselves that it's meaningful.