Nice looking guitar
Raisinbrain. Pity you had to result to filing the bridge. Kinda crude but hey, it's an Epiphone part, and it gets the job done eh?
Yeah, you're experiencing the key frustration with restoring/upgrading many of these instruments, metric versus imperial measurement. It can be maddening to be "just" a millimetre or two off! As you're seeing it does mange to screw up playability very nicely.
When you have time, try to take some accurate measurements and then have a sniff around some of the web sites specializing in parts Made in Japan. You may find a more suitable replacement there, albeit likely at a premium. Good 'ole eBay may yield something too. Have a look at Wilkinson parts in particular. They are generally good value for the money.