Ideally, morning weight+gear=middle of range. There's some give and take here, though. If you can't land in the middle of the weight range and are looking at the top of the range for one boat and the bottom of the range for the other, you would typically lean towards going with being at the top of the range for a playboat so you can throw it around easier and the bottom of the range for a river runner or creeker.
"The world would be a better place if everyone kayaked."-Brad Ludden (Valhalla)
"You only get one chance to run a drop blind."-DD