Does anyone recall the measurement limit of the tire in which
 

the insurance company will cover the warranty and replace with a new tire..ex: 4/32??? i have a nail in my tire and wanted to know

I would think it would depend on who the tire insurance company was, and what their policy is. If your policy doesn't say, why not ask them?

Most pro-rate the covered amount by amount of tread left. Example, 8/32nds would pay for 3/4's the cost while 4/32nds would pay for a third.

Depends on the policy, but most 'additional' (ie you paid for it) road hazard plans will replace the tire if it has ANY legal tread. (ie above ALL the wear bars)