Really appreciate your advice. I'm a math and science guy by training so tend to overthink all this stuff. Was out in the shop tonight and really looking at the rear wheel placement. As they come from the factory the rears on the LX3310 are very tight.
So I got out my tape measure. The OD on the rear tires (R14s) is 53 1/2 ". It looked like 3 1/2" would put the center line of each tire right at the edge of the rear fenders, so half the tire would be inside the fender and half out. Not sure if that's good logic, but it is some logic. That would result in a 60 1/2" OD on rear tires.
I run a 6' (72") rear mount finish mower and always want the mower wider than my rear tires for going along edges. I also just picked up a flail mower that can be hydraulically offset to reach out to the side, so edging will be even less of an issue.
Your advice, plus some other info I've read, make me inclined to just leave the front alone for now. If for some reason things don't feel right, I can always tweak the front later.
Appreciate any other feedback. Thanks much!