I use micro bits, bought by the dozen. I use a dremel tool with an extremely small collet. I put the dremel in the plunge router base and drill my holes that way.
I did install the guides. Then I needed to re saw some thing. I did not change back to the thin blade. Then my cusband decided to cut a VERY THICK hunk of wood into a circle so he could mount it to his lathe. Now I need a new blade. I haven’t put the thin blade back on it yet.
I replaced my Dewalt 12” miter saw with a Dewalt 12” sliding miter saw. The saw came with a “washer?” type thing adapter because the arbor is a different size.
Just so you know.
I often use both flat and spiral blades on fretwork. It depends on the space that’s being cut. When it is smooth or pointy, flat.
Where it’s feathers or simply doesn’t matter, spiral.