Knitting a Multicolored Vest

I've been busy knitting away on a heavy duty vest in many colors. It's so fun to knit in a riot of colors on big needles.  Truly loving it. I'm about to the point where I can add the arm holes. The back and sides are knit all as one unit.

And I already bought some white and off white yarn to make another one.  But I'm going to cut back to 3 yarns held together instead of 4, because I don't need 2 heavy vests.