You talked about carrying the gun and Marlins are noticeably heavier than the Winchester. That said, they are a stronger action, though no complains about the Winchester. Also, the added weight will reduce recoil. Again, not than most complain about the 30-30 recoil. But less recoil generally means the shooter generates better accuracy.

I like the idea of the side extension for the hammer and might grab one myself.

Another idea, which I added this year but haven't tested, is a peep sight. This should increase accuracy a good bit and I don't expect it to be a hinderance, such as snagging on things, etc.