You mentioned the cost of a metal adapter sleeve. Another option might be to make your own. I have a piece of acetal you can have. It's probably 2x2x10. You could turn the sleeve and then tap it for 1 or 2 grub screws to hold it in place. You'd then be able to use any 1" tool posts/rest combinations.My banjo has a 1 1/2 hole for the post. The post has to be .010 under 1 1/2 to fit. My tool rest is solid steel 1 x 1 1/2 x 12 inches welded to the post. I looked at buying a new banjo but I think it was over $300.