Like you said, I'm assuming you don't intend to perform major surgery, but close wounds. The finer the gauge, the more easily it pulls out. For external sutures you really want monofilament. 16 -20 gauge monofilament, in my opinion is, is perfect for basic suturing. They're big enough to hold most non-life threatening wounds and small enough for most people to endure without local anestetic. Keep in mind that closing a dirty wound will be worse than just covering with clean gauze and anti bacterial ointment. I carry a very complete medical kit with a surgical kit, but will always question myself as to whether or not to close a wound or just scrub thoroughly and cover.