Roller furling
You ask what parts are "extraneous" and which ones are needed. I think there may be a fundamental misunderstanding here. Roller furling units are self-contained add-ons. You don't make one from the parts that exist on a boat that is not so equipped. There have been lots of posts and threads about this topic in the past. Check the archives. For my money, the CDI roller furler is the best value. I have had my CDI roller furling unit for several years on my Oday 23, and I have not had one issue with it yet. You will have to have your existing sail modified for a roller furling unit; it will need a tape sewn into the luff, and a foam insert added to help hold the shape. It may need to be slightly recut too as the sail will likely fly a litter higher off the deck than before. You will also need some type of block arrangement to bring the furling line back to the cockpit. For a 22, I am guessing that means a stand up block affixed to the bow pulpit, and one or two blocks affixed to the stanchions to lead the line back. You will need a cleat or some other sturdy point to tie off the furling line too. Installation of the CDI is relatively easy assuming the mast is down. You will probably be able to use your existing headstay, but there is a chance that you will need a new one if the existing stay cannot be tightend up enough to accomodate the furling unit. Who can do this work for you? I paid my sailmaker to set up the unit on my headstay, but I installed the whole shebang on my boat. I bet that whoever you get to modify your jib can do it too. Also, check with your marina; I'm sure they can do the work, as could any rigger. That being said, if your marina is anything like mine, if you ask one guy there for help, you are almost immediately surrounded by a whole bunch of guys. You also mentioned "self-furlers"; I don't know what that refers to, so I can't comment on whether they are cheaper than roller furling units. I think when all was said and done, I paid my sailmaker about $800 total for an assembled CDI furler and modified jib. I installed the assembled unit myself (with help from the marina crew).