The 1.5 oz allows a little more abuse.
Alan, I also have both the .75 and 1.5. Our Wed night league doesn't allow spinnakers so both don't fit into any of my racing wana-be fantasies. I use the 1.5 for the stronger breezes that combined with my inexperence would probably ruin the .75. As you said, the 1.5 is easier to fly single handed and works better for a wider range of wind angles under those conditions.I did install telltails on the 1.5 and found out that in my case they haven't seemed to make any difference. Basic sail shape seems to provide a better picture of what needs to be done.Ray