What works fabulously well is to put two carbon fiber windsurfer mast BASES, base to base for a double tapered spar. For a spinnaker the only support that is needed is at the end of the pole and a bit of line at the bridle to hold the pole up wile rigging and to induce prebend. You do need to make or get a base to base ferrule, the ID of standard masts is 1.91". I was using some very expensive carbon fiber ferrules, but after analyzing breaks by others when the tip guys failed, I think the best ferrule is a piece of PVC. That way if you have a failure, the ferrule breaks and not one of your bases. I haven't acutally tried the PVC yet, but properly rigged, almost all the load at the joint should be compression, with very little stress on the ferrule.I have a few mast bases left and a few tips that could be used for righting poles, email me if interested.