Andy,
The CG limits are firm for any weight of your ship. Its up to you to add trim
weights to bring the CG back to desired with a heavy pilot. I set up my ships
for ideal CG without wing water. When I load water, I must add weight to the
tail to compensate for the forward CG shift caused by the wing water. Many
ships will have a tail water tank to accomplish this.

That is, unless I'm flying the Genesis 2, then I must add water to my nose
water tank, because the wing tanks are aft of the empty CG and wing water
causes the CG to shift aft, so I must compinsate with forward weight in the
form of nose tank water.
JJ Sinclair