jrockbridge
Stealing Your Riffs
I may possibly have the screws you need, but they're not special screws at all. As long as you get the correct thread your local hardware store should have them. Those would be metric.
That said, you could always upgrade the bridge on the cheap, too. I just put this bridge on my Harley Benton since the stock bridge was a bit buzzy and had the dreaded lean. For under $20 shipped with tax it gives you individual saddle adjustment, but getting longer screws for your current bridge will probably cost you a $1.
It would seem that my Gretsch fingerboard radius is 12" like a Gibson. Would a pigtail style, adjustable wraparound made to fit Gibson work on a Gretsch?