3/4" UHMW backed by 1/8" 6061
- definitely chamfer the edges
-1/8" steel works if you're on a budget and not concerned with weight (at least its down low) but isn't necessary for strength, dimpling the aluminum definitely doesn't hurt. Its just there to provide rigidity to the UMHW
-1/2" UHMW works too but the 3/4 gives you a little more meat to countersink your hardware, and if you are super abusive on it and will hold up through a few more wheeling seasons. A lot of that would depend on where you wheel most, if your local park is filled with jagged dryer rock (choccolocco is the best example I can come up with in the SE) I'd go 3/4, if you wheel big slick rock (gray rock) you're probably fine with the 1/2".