Sounds like you took too much edge off the sear. You can re-grind the sear angles to a 90* and start over. Then polish the surfaces carefully. Rather than sandpaper, I use a super fine polishing wheel from a Dremel tool polishing kit. DO NOT USE IT ON THE DREMEL. The edges on the polishing wheel are also great for getting into the reaches on the hammer catches. You really don't have to polish much on the Beretta, they are pretty smooth to begin with.
Here is what I did to my 92G Elite for Production comp;
1) Polish the hammer and sear mating surfaces as mentioned above. As well as the pivot points of same.
2) Polished and smoothed the mainspring strut, including the pivot.
3)Slightly tweeked the sear spring to reduce the friction of the sear to the hammer. Be very careful here, a little goes a long way.
4) Polished the firing pin block and removed 1/16in from the spring.
5) Polished the inside surface of the trigger bar.
6) Polished the trigger ears and replaced the trigger spring with a Wolff reduced power trigger spring. The Wolff unit makes disassembly and reassembly easier, and in reduced power, I have had no problem with it feeling gritty.
7) Install a ISMI 15lb 1911 mainspring. This spring alone is too soft and you must add a 7/8th in. preload spacer to the spring strut.
8) Replace Elite hammer with Elite 2 hammer.
This has resulted in a 5.9lb DA and a 2.5lb SA that is smooth as glass and 100% reliable.
I have done other things such as solid guide rod, grips, Dawson front sight, adjustable rear sights and an over-travel stop of my own internal design.