It has been my experience making wooden cups, that pure slip ons are the way to start. I use a 2.5 hole saw for the outer. For the inner, I used a 2 inch initially, but the fit is sloppy (too loose), and the wall thickness that results is too thin (visually). That is why I ended up using a variable hole cutter for the inner circle. Mine were too aggressively sanded with a dremel and not enough test fitting, so they are still a bit loose, but some blu tack holds them in place fine.
I made 5 sets before I got what I liked. I could have experimented with mdf, but thankfully the wood I chose is not that pricey, and the place is literally 5 minutes from my house.
Keep at it, it is rewarding when you get it right!
I had my 60's recabled yesterday at a local meet, with the Mogami and the Vampire 1/4 plug. Works great! Thanks again FallenAngel!