Hi!
It's always good to see a 3-railer convert :-) I do all the work on the Sherline. I love the "NWSL The Quarterer III", a great tool. Proto:48 is my thing, all and everything has to be machined. I personally would not convert 3-rail because it's not really worth the effort. Exceptions are super rare locomotives or such not being made in 2-rail.
Sarah