Stephen:

I would first get myself a good book on the theory and practise of sailing
and learn a bit about sail performance and terminology. You seem to be a bit
mixed up in your terms.

A 135% genoa (any good sailing theory book will explain how this is
measured) is generally the best all around compromise. If you generally sail
in light air, a 150% might be better. If you routinely sail in heavy wind, a
100-120% would be better.

David