hmmmm beez .. wanna tell me what you do for a living so i can get a job doin it too? 37 inch crawlers .. looks like 17 inch aluminum rims ...... not to mention all the other stuff hangin off it.. whew.. looks ......
just a thought that might help you out: get a bunch of aluminum welding rod and tack it together at the ends and try using that instead of string. That way you've got a solid mock-up device that you can also use to model your architecture and swing clearance.