Dem Bart
I have used Dem Bart tools for years and am very happy with them - The LPI depends on the wood and the useage of the gun - soft wood or hunting guns generally use a coarser checker -(18-16 LPI). 24-28 looks nice but is a bit slippery and a lot more work. I use a lot of 20LPI as a compromise on decent walnut.
Have fun and practice a lot before ruining a nice chunk of wood - An eyebrow magnifier makes life easier too.