Well I adjust my speed depending on if I am hitting the grass or not. I want to have my jig just above the grass most of the time, however if it ticks the grass every now and then that is good.
Also can use a heavier jig to get deeper and smaller one for shallower water. When I catch fish I know it's right so that is where I try to keep my speed.
Just my personal like, but I use a 1/32 OZ. marabou roadrunner most of the time in water 4' to 6' deep this time of year.