Yes Mike, I have tried circles and now use them as well. those gamakatsu hooks sure are sharp, I swear by them chunking for tuna. This year I am plannning on running a couple of herring from my new homemade downriggers.
I took a window sash weight and welded a nut to the end of it. then i took a downrigger release clip and secured to the nut. I tied rope to the end and I have the rope marked off with knots at certain lengths and that will allow me to lower the weight to the desired depth. I tested it out at the end of last year. I was worried that the release clip was going to stick when a fish hit it but it worked great. I can't wait to see what is waiting around this big boulder i know of in about 50-60ft near one of my favorite spots. I know there is a big fish lurking around the vicinity.