Haven't made a resonator yet -- I've got a UKE body that I've stripped the top off and made into a 'CBG' with a  grill that looks like a resonator...figured I'd see what it sounds like just as an acoustic port first...I found a little thin stainless  medical or restaurant dish that sounds pingy as hell, but thought that might just play up one frequency...will have to experiment with random items as resonators...--- you may be able to buy an actual one --- some tiny little thing that might not cost too much....as for frets...I have zero intention of doing my own frets  yet...tough enough getting them done as is......I've been just making these as slide guitars with fret markers --- playing straigh 3-string  has actually taught me a ton with slide trying to 'fret' melodies on individual strings...  will have more to post soon...  almost there with the UKE rebuild  ET