Vic - no problems with the stanchion base, assuming you have backing plates/washers on the through deck bolts. This last season I upgraded the blocks at the stanchion base to
Ronstan Series 55 automatic ratchet blocks. This helps the person flying the spinnaker so the cabin top winch is not needed in light to moderate air. It is easy to switch the block from between ratchet, no ratchet, or load sense ratchet (runs free unless it senses a load).
As you note - it keeps the spinnaker leads out of the aft cockpit area.