going to a transom lifting point the angle of the bridle would be too shallow, allowing rotation, if the keel lifting point is used. A steep angle would be better for control. If the hull is going to be supported by the keel bulb, then the amount of weight should be minimal ( enough to keep the boat from rotating / transom dropping ) as the boat is lifted. ( some are using a few water filled 5 gal jugs on the bow for balance ) I'm thinking the the fairleads moved aft on the jib track should be strong enough and allow for a good angle to the keel lift point to keep the transom from rotating down. ( The fairleads and jib track are rated for a few thousand pounds of load while the load to balance would less than a couple hundred pounds )
I think your math may be off on this - though I am no expert. I amount of weight people are loading on the bow is at least 200 lbs which is 15 ft forward of the center of gravity, so the force closer to the cg is much higher.
It seems to me that if you have 200 lbs on the bow (which is about/at least 15 feet forward of the center of gravity) the torque force you are creating is 3,000 ft-lbs of torque. (Force x lever arm = torque) If you were to lift just 3 ft behind the cg then the lifting force would be 1,000 lbs. (3000 ft-lbs/3 ft = 1000 lbs.) The further back the lifting point, the less vertical force required.