To get close to 3lbs you'd probably need a 3.5 connector which actually brings the trigger to about 4.5lbs. Then a 6lbs trigger spring. It's a heavier than stock spring but that spring resets the trigger, pulling the trigger does not pull against that spring in fact the spring slightly aids in pulling the trigger.
You might end up with 3.75lbs, maybe 4lbs with that set-up. They do make "2.5" connectors but I've never heard of someone using one. Anything beyond that you might consider a rounded firing pin safety, like the Lightning Strike one and professionally polished parts. You could polish the parts yourself(aka 25 cent trigger job), but it's very easy to remove too much metal and if you remove too much the gun either won't function or it won't function safely. If I were to do a 25 cent trigger job, I wouldn't polish the firing pin at all because it costs like $40 to replace.
The "3.5 Rocket" by Ghost Inc can reduce over-travel and give a more positive reset.