I have a 69 RR. I installed split monos +1 and cal tracs. I found the height a little too tall and added a 1 inch spacer. I had a 30x9 slick under it and it fit without the the 1" spacer, and fit well. I now have a 31" tire with the spacer. It's a wee bit tight. I also have sliders; no shackles...fwiw.

My next plan is to install wooden spoke wheels of a horse drawn buggy.