[willy]

My 85 cuddy with full transom has the corner drain holes that drain into the hoses which connect to thru hulls on the side. All 16 V20's I checked out had this arrangement.
They did raise the floor level approx two inches at some point late 80's due to complaints of water coming in the thru hulls. It did not eliminate the problem but reduced it a lot.
A lot depends on the power arrangement you have. For example even though my motor is on a bracket sitting 30 inches off the transom(previous sea drive) the scupper drain holes outside sit approx two inches obove the water line. That is I believe because I have a 4 cylinder 115 Johnson. I test rode two V's that had a 225 and a 200 horse V6 and they were approx same year and they both had drain holes that sat below the water line. Both of them took water in and out constantly from just minor rocking and wave action.