Leaf spring theory question

Centering the wheel in the opening with larger diameter tires. Was reading about the spacer blocks and contemplating the multiple ramifications. Does anyone know of a vendor that sells 1/2" aluminum spacer blocks?

Gonna throw rear shackle angle off, pull driveshaft out 1/2'' (same as spacer), take a little weight off rear wheels , if ur on the ragged edge of traction = bad.