An 1.5" hole saw will give you 1.25" circles. I cut mine as thick as I can then square then with the hole in the center as much as I can. Stack them up on a mandrel (I use a chunk of the .25 OD stainless tubing from the hardware store), coat the mandrel with wax or some other release agent (beeswax or paraffin) and glue them together like you would a cork grip with a grip clamp. Turn to desired shape, seal, ream, install and fish. You can use shellac or sanding sealer to seal the bark so it isn't soaking up moisture o you.