Yeah, it can be trial and error. Leave what you would consider to be the "max". Then just tape them together, and test fit them. What I did was combine the 2 methods of attachment. I overlapped the pieces and glued them (with ABS cement) and then put a strip down the center too. The thigh pieces can be a bit bigger because they float, besides you have to be able to fit your foot through.
The calf pieces need to be big enough to fit over you boots, but allow enough room for your ankles. I did have to pad my calf pieces near the knee because they rubbed.
The arm pieces are glued on both sides, and need to be left big enough to slip you hands through. I have thick padding in mine to allow me to shove my arm through, but it keeps it tight on my arm and doesn't slip.
The cod and ab plate need to be left big enough to be able to take a deep breath without busting open. The chest is attached with elastic on the sides, so you have enough room.
