I ran stock L26 rockers, lifters, and valves. I didn't need to shim the rockers. It's a good idea to measure your pushrod length....the standard pushrods that zzp's sells with the XPZ are what I needed, so I lucked out. But, you should still invest in a pushrod length checker. They are cheap. Unless you are running different than stock valves, you probably won't need to worry about shimming the rockers.
I didn't have use for the car anymore, so I sold it. But, the guy I sold it to still DD's it. It was a fun car. Only thing I didn't really like about it, was the vibration that the double roller caused.