geometry

I was reading a thread concerning front end geometry and the presence of " offset" as opposed to 0 degree "offset", Is this referring to the placement of the axle to the center of the fork tube?:confused:

I'm not sure if this matters, or if I would notice the difference, but I was just drawing up the triple plate design for my fat tire bike and got to wondering... If the triple plates have offset built in (the fork tubes forward of the pivot point) should the handle bars be mounted in line...

I have a GX160 that I am installing the Champion style shaftmount rockers, I have uncut cromoly pushrods and I and going to have .030 milled off the head. How do I make sure all these variables are set up correctly...? More specifically how do I determine the install height on the shaft...