I spent at least 5, maybe 6 hours working on getting it to sound/play right.
A couple hours in, I ended up taking off the big plastic see through string guard, it was much easier to work on. Lubed it's wood screws while it was off. Also lubed the buzz bridge screws while it was off too. I used D'Addario friction remover (like Big Bend Sauce) The screws are just going into wood. The buzz bridge screws move very smoothly now with little turning force needed. It was
much easier to work on
I set the 2 front screws 1st for action height, 4/64" high E, a hair over 4/64" low E side. Then I adjusted the single back screw that pivots the bridge to change where the strings actually have their 'take off' spot. This adjusts the intonation.
I got the action and intonation really good, it's hard to see with the harmonics from the buzz bridge. I had to check each string at the 10th fret sometimes to get a clearer reading of where I was at.
But, the problem I kept running into was getting enough sustain from the high strings with the intonation and action set right. The high strings had way too much contact with the bridge and the string then had almost no sustain. I was getting great buzz from the 3 low strings but the top 3 were choked off. So close!
I did find a guy at a guitar store here that has had 3 of these electric sitars. He still has 1 of them. He said he had to the shim the bolt on neck on 1 of his to get it to work right. He said I could bring it in and he'd show me how he sets them up. I might end up doing that. It's a 4 bolt neck like a strat but no metal plate. I have some maple strat shims for Stu-Mac. I think I'll try that today.
This bridge is very sensitive to any adjustment. And there's only so much play in the amount you can pivot the bridge. Plus there's too much downward pressure from the strings on the back side of the bridge. And that's with a set of 9-42. At a certain point when you loosen the back pivot screwq the bridge can't tip up in the back anymore because of the back sides downward string pressure. I added a 2nd spring to that back screw, didn't help much.
So if I can shim the neck a little and give the neck a little relief it might do the trick.