For sure on changing tire size affecting toe. As for the tread center, toe is a differential measurement, comparing front of tire to rear of tire. If we assume a 6" wide tread, the differential front to rear will be the same for the inside, outside and center of tread, seems to me. Different overall numbers, inside to outside, but equal differential. The IFS, and having it loaded is another issue that throws a wrench in the works.

The picture sure made it look like an easy way to attack the problem!!