I made two cuts through the SQUARE blank with a wide (3/4”) bandsaw blade, then glued in the veneer, BEFORE putting it on the lathe and turning it round. That way, assuming the two sides of the blank are parallel, you can put a strip of the veneer in each cut, put glue on every surface, and clamp across the blank with a few Jorgenson clamps. This one’s about 12” in final diameter, so the blank was probably 13” square. The glue surfaces of the blank were sanded by hand to be sure they were square to each other and with no gaps. When you put the final tighten on the clamps, take care that nothing rises up. I do all this on a Melamine board, the glue won’t stick to that (much) and if one piece or another does rise up, you can tap it back down as you tighten. If you don’t have a piece of Melamine that big, a sheet of wax paper underneath is almost as good. I use Titebond I (original) glue. Once the glue dries, get rid of the squeeze-out and center your waste block on the blank. Then bandsaw it round and t’s ready to go on the lathe. As you turn, measure thickness frequently and keep the gouge sharp. Really sharp.