It's not that difficult to
rig a pole lift - esp if you're happy to have it all external. It could be mounted as low on the mast as the spreader height. In fact if you don't want to drill holes you could lash a block to the spreader roots.
Flying the
spinnaker in light air will be virtually impossible without a easily workable pole lift (adjustable from the cockpit is best). In heavier air the sail will support the pole, but as suggested above gybing cleanly will be much more difficult.