I've had this idea for a while. While doing a layout I was thinking about measuring the existing saddle positions (properly intonated), which led me to think about scale lengths, compensation, and intonation. The fixed saddle should be made in the proper position for good intonation.
Last night I tried adjusting the saddles for proper intonation. Only to find the G & E are still flat with the saddle all the way forward. The hard part was you need a 7/32" wrench to adjust the saddles, but the wrench won't reach far enough down to the flats without pushing the string down. So I made an extended length wrench with additional clearance for the strings at the bottom. I finally used my mini milling machine to make something!!
This helps with adjustment, but not the intonation problem.
I'm going to check the actual scale length (nut to 12th fret X2) and the strings lengths tonight.
There's no sense making a bridge insert if it makes the intonation worse.