By the way, the average mileage calculation for the front-to-back, new front rotation scheme gets very complex really fast. Seems to end up after a while at one tire per 750 miles like the simpler scheme.

Just did the calculation: Okay, the function determining tire mileage under the 1000 rear miles, 3000 front miles oscillates around buying one new tire every 750 miles gradually settling on 750 at around the 7th tire purchased. Due to the first tire replacement at 1000 miles, however, the average mileage/tire stays sitnificantly above 750 miles for much longer than that. So for most folks, the average tire purchase mileage over a pretty long period will stay several % above 750 miles. Keeping the tires in place and riding each if them to end of life will always be at a tire replacement on aversge every 750 miles. Surprisingly, I was right at the outset. Best mileage is obtained with the rotating scheme, even if only by a little bit.