Brake pad thickness?

[supercub]

I want to check my brake pads and was wondering what the minimum thickness is. How thick are they when new? I have about 18,000 miles. What's typical mileage to change them. It's a W-20 I believe.......03 Southwind 32V. Having Goodyear G670RV tires installed and I want to look things over while they're off. By the way, I see some people opt for load rating G but I stayed with F, like what's on it. Hopefully this is ok. Thanks
Also, what's the torque for the lug nuts....are they the same for the fronts and rear with the dualies? Thanks again.
Brian

[supercub]

I want to check my brake pads and was wondering what the minimum thickness is. How thick are they when new? I have about 18,000 miles. What's typical mileage to change them. It's a W-20 I believe.......03 Southwind 32V. Having Goodyear G670RV tires installed and I want to look things over while they're off. By the way, I see some people opt for load rating G but I stayed with F, like what's on it. Hopefully this is ok. Thanks
Also, what's the torque for the lug nuts....are they the same for the fronts and rear with the dualies? Thanks again.
Brian