Does your boat by any chance sit in a cradle instead of on stands? We figure out the CG of skids we build so we can cut the forklift pockets in the right place. We put a pair of railroad toe jacks on either side and lift the skid 1/2" or so. We keep moving the jacks towards the heavy end until it balances.
You might be able to do this for a keel boat if your keel is sitting on cross beams so the jacks would fit under the keel. You'd lift a little and watch whether the boat tends to tilt fore or aft.
I've built trailers for a Catalina 22 and a Hunter 27. They trail best when you have at least 200 lbs of weight on the tongue, depending on the size of your tow vehicle. Any less and braking hard will be really exciting! This is also true if your boat has a deep keel, which puts the center of gravity real high. Then I'd load the tongue weight even more.