M16 3 round burst trigger sourcing and parts differences

I'm getting the quirks worked out on 3 position binary which uses a M16 3 round burst trigger and two disconnectors.

1. Sarco is the only place I've found that sells the triggers individually and the sear surface on theirs looks like 💩. Any other vendors that will sell the 3 round burst parts individually?
2. Are the 3 round disconnector springs the same as standard AR disconnector springs? I couldn't find any 3 round specific springs and used AR springs. They work but they don't seat well and I can feel the coils rubbing/ binding when manually compressing the disconnector. You can see it in the right side disconnector.