I used the Amana 51404-k bit and it produced pretty nice cuts. This foam was in layers with glue between so you could in theory cut the perimeter and then peel up the layers to the depth you desired. In practice it didn’t peel that well so I just cut pockets to the depth I wanted. Only issue was when one of the pockets was at the exact depth of a glue layer. It was a little messy then, other than that the bottom and the top cut cleanly.