Greetings, I cannot seem to get my low E and G strings to intonate properly on my mid '70's Gretsch Broadkaster semi-hollow six string guitar. I have already swapped bridges (tune-o-matic), lowered the pickups, changed saddles, changed strings, etc. It has a zero fret so I assume I can eliminate a nut problem (correct me if I'm wrong). Neck relief is flat with no buzzes, and string height is within specs. The saddles are all maxed out to the bottom and the E and G strings are still sharp. I have setup guitars for years with satisfactory results but this thing has me frustrated. Any ideas? Thank you.