Ok, correct me if I am wrong. . .
You are ENGRAVING letters into a mold. The part produced by the mold has RAISED letters. There are no RAISED letters in the mold. So there is no need to talk about raised letters.
I would not expect to be able to see anything a .0059 inch diameter did. I have the same issue with the laser on my machine. I have it set at .007 diameter. You should be able to see the preview if you set your preview quality a lot higher. If I use Standard I cannot see what the laser beam is doing at all.
By the way, I do not know why you expect to be able to see the tool cutting if you OFFSET the tool above the surface. Think about it, if the surface has been cut and you offset above it there is nothing there to cut so you should not see anything.
Low Profile CNC Router Vise