The industry terms "Transference Ratio" and "Inter-Axle Ratio" address the whole lead/lag 4wd thing. The question is how much difference is best. On tractors with "front wheel assist" 2-6% front "lead" is common practice.
From any models parts lists its possible to follow the gear tooth count from the rear drive pinion to the front axles - for example my L5450's "Transference Ratio" calculates at 1.508 : 1 (front axle turns faster). This can then be applied to the rolling circumferences of the actual front and rear rubber to get the effective "Inter-Axle ratio". For my L5450 its around 1.04 (front pulling). That's a good ratio, not outside the "skwirm" tolerance for most tires. Its still a good idea to take it out of 4wd on pavement to limit wear.
Pretty interesting subject - especially finding every bevel and planetary gear tooth count in your model so you can calculate it. Sometimes the owner's manuals publish it. More related reading
here.