So here is my attempt to explain how I line up my angles. It works well for me.
1. Put angle cube on the heavy base in front of the blue metal base of the WEPS. Zero it.
2. Lay the angle cube it on its back flush against the lip of the blue base (It will read “error”) lay a stone against the angle cube. It will stick together due to the magnets. slide them so the tops are both flush against the lip of the blue base. (Now they are both laying flat on the big base and flush against the blue base.
3. Then put the stone/cube assembly on the rod.
4. Use a straightedge across the black jaws and the stone/cube while it ison the rod. It will be vertical (or close enough) so that one can obtain a repeatable and accurate reading. Now set the angle as you would normally do.
Sorry for the cumbersome description. I’d show pics, but I just can not get that to work yet.