I've towed with a 3:73 with the 3 Chevy D/A's I had. Have the 4:10 on the Ram.....and last two Dodge trucks I had....Can't really tell that much difference, maybe comparing a 3:42 to a 3:73 or a 4:10, towing heavy in the mountains, could probably tell a difference between those...but, though we know there is a difference, I don't know if it would be worth it to go from a 3:73 to a 4:10...you would pick up more GCWR, though you couldn't change whatever is on the doorjamb placcard...
Don't know if it would be worth it or not to change the gearing,. Why do you think it would "tow better", just going from 3:73 to 4:10...?
What are you towing, GVW?