Know it dont help your Browning any, but Savage just re-modeled their 20ga slug guns to include theire accutrigger, so it is fully adjustable from 2.5 to 6 lbs.. I have one and it is simply awesome. I sold my 870 wingmaster as soon as I could.
Like I said, it dont help your cause right now, but you know how it goes. If one maker makes something nice the rest are sure to follow eventually.
I'm sure if Timney is making one it is ALOT better than the factory trigger. Check with Rifle Basix also to see if they make one.