confused on off sets

[southpaw14_2004]

I'm going to buy some 20 inch fuel hostages and I would like to run 35 inch Toyo MT Tires. All the packages I keep finding are a 12.5 offset and I've read a few articles saying that they would rub and break cv joints etc. My truck will be on the mid perch mod when these wheels arrive. My truck is primarily used around the farm, hunting and moderate off road use. What is the max offset I can use before it becomes a rubbing issue?

 

[pat'sRAPTOR]

Here's a thread that explains the wheel offset hope it helps.

http://www.fordraptorforum.com/f25/wheel-offsets-explained-19376/