While visiting with another weaver the other day, we were discussing using raddles. I said I was working with a very narrow warp and she suggested I use rubber bands on the back beam to help guide the warp over the back beam. Well, I couldn't find any rubber bands, but used instead some nylon loopers.
This is my hand painted silk bookmark warp. It is only 3 inches wide, and using these loopers helped me get this warp on. (I went front to back) !