I am planning to replace my rusted tub this winter with AL tub. I found a frame with OME springs, front shakle reversal, and tires/wheels. Now the questions, PO replaced front and rear bumpers with homemade, front is fine, rear has no cutouts for lights and looks shorter to me. It also as no means for attaching tub to it. Thoughts on attaching frame & tub and/or putting lights in boxed rectangle rear bumper. Is there a way to check frame length? I tried meassuring from axle to shackle eye in back, but different spring lifts seem to change it. Thanks