On Feb 15, 6:55*pm, Art Unwin wrote:
I was basing efficiency on all forces being accounted for
with a higher gain resulting.

Whether or not you account for all forces will not have any
effect on gain. :/
This is another case of the hopeful free lunch..
But the cupboard was bare.
The radiation from the vertical and horizontal polarizations
added together will never end up being more than you started
with.
And an antenna that is a mix of both will be a compromise
if the other antenna is purely one way or the other assuming
no reflections, etc skewing the path.
No free lunch..