It might have been one of your club officials that contacted me about the handicap.
In Victoria we have top Mosquitoes racing with and without spinnakers and really 80 is not far off the mark. It all depends on the conditions who comes out on top.
I think if you really want to silence your fellow club members, try racing without the spinnaker on 84 and see how you go. If you are beating the "faster" boats around the course with the spinnaker you should destroy them on handicap without it.
Another thing to remember when talking about the Mosquito handicap is that the A-class, Hobie16 and Mosquito are the only cat classes that put in enough results to Yachting Victoria to qualify for a "reliable" handicap. If other classes have a problem with their handicap then their class associations need to send in some results and talk to YV and not just whine about it in the club bar.
Over the years I've been racing with the spinnaker I've been beaten by Taipans, A-classes, Hobie16s, F18s, F16s, Nacra 14, Nacra 5.8 and Tornados amongst others. I've also beaten plenty of them so I don't see any problem with the handicap.