I wouldn't advise doing it.  The M-1 Carbine, without a LOT of work (some of which will diminish any collector value it may have) is not a target-grade rifle that will greatly benefit from a trigger job.  You can carefully hone/polish the engagement surfaces in the trigger mechanism, and lube properly; if you want more, send it out to someone with experience, and who won't ruin it or cause it to be unsafe.  Perhaps others know of gunsmiths that can do this.  Good luck!

Measure the pull with a gage.  5.5 to 9 or so is about right.  Guessing is hard to do.  A good lube will smooth the pull, but like the other respondents I'd not diddle with this.

Why not get a spare trigger assembly from Fulton-Ammory or J&T surplus and let Fulton work on it for you? I think his trigger jobs are like $40 on them. You'd have the original stock collectors assembly and another for one for plinking with.

I got a M-14 trigger assembly from the CMP for $40 and my plans are to have Fulton tweak it for my M1A.