I'm usually satisfied with the the results I get marking with a sharp pencil (Erasable!). However, I'm going to be making a lot of loose tenon joints and I need to be able to fairly accurately and repeatably find the centers for those joints and I'd like to be able to do it without a lot of fumbling around. After some research, I think a wheel marking gauge would be better than pins or knives. There is a huge difference in what you can pay for these and the thrifty Scot in me is arguing against spending too much (so many tools, so little money). It seems to me the biggest necessity is the ability to hold a setting. Next would be cost wise so I can get more than one. Thoughts, recommendations, experience?