The lake I fish has a little more thick grass than other lakes so I have been using the 1/4 alot lately with success but use the lightest weight you can get away with. As for colors of worms, for low vis/muddy water go with bright colors and for clear water go for natural colors. Some people prefer dark colors in low vis water and that works to but I just prefer bright colors
EDIT: If your looking for specific colors I like chartreuse, green pumpkin, black, June bug, yellow, and brighter greens those are some of my favorites but almost any color will catch a fish eventually just some can be more ideal at times.