There's alot of variables here that will affect what kind of knife you will find comfortable to carry.
What kind of clothes do you wear most of the time?
What kind of environment do you work and play in?
What kind of cutting jobs do you run across in your normal day?
Usually a 3 1/2 to 4 inch overall knife length is comfortable in jeans, but a little bulky in Dockers, let alone dress pants. A 3 1/2 stockman with square bolsters will be a bit more noticable in the pocket than say a 3 1/2 inch barlow, with a slimmer cross section and only two blades instead of three. But a 4 inch single blade trapper or famers knife will carry in a pocket easier than a 3 1/2 inch stockman.
Try alot of different patterns and see what suits you personally. With traditinal pocket knives there's so many diffferent ones out there, it's like being in a 31 flavor ice cream store. Some people like rocky road, some like mint chocolate chip, some like plain old vanilla. Everyone here has been through many patterns in thier life. Also the older you get, your tastes will change with the years. I used to carry an almost 5 inch sodbuster, now I love a 3 1/2 inch scout knife like I carried as a kid. Came a full circle. I also like the smaller knives as well these days, like a peanut. Peanuts are fun knives to collect, lots of variance and handier than you would think from thier small size.
Maybe try something in the middle of the road to start off with. Maybe a 3 7/8 stockman, or regular size barlow. If they seem a bit too small after a while, try something bigger. If they work out, fine.
Good luck.
