I don't know what those exact tires are, but HPI Super Radials are comparable.

When making body-post holes, I find it helpful to balance the body on the posts, figure out how much to cut off the posts to get the body to sit level (not at final height, just level), make the necessary cuts on the body posts, and THEN center the body on the chassis and mark the hole locations. I screwed up a couple bodies thinking that the hole locations would be "close enough" if the body wasn't sitting level above the chassis; I was wrong.