Valve cover risers

[80Chevy4x4]

Has anyone used the valve cover risers to help clear the intake...I installed an aftermarket intake and had to grind down the old valve covers so the would fit flush and seal( it was hitting the intake runners) I ordered 3/8 risers so my new aluminum valves would fit right. the clearance is perfect now...my question is what gaskets would you use with them and if anyone had any problems with them.