There is one more drawback of a poleless spinnaker.

You have less refined control of the spi luff. I jury rigged a similar setup as Kirt myself one time and found that the tack of the spi would move backwards and forewards with changing sheet tension (acting on the clew corner). The tip of the pole is very much fixed as the top of the spi sail is near the mast. This makes for better control of the spi luff with sheet tension in my opinion.

I had forgotten to include this aspect last time

Wouter