But you can certianly genetically modified it to make it five times bigger (why not... it is unproven)...

But I agree that ten times this number (efficiency of 50%) will be the most you can get..

SO you should do the fficiency number using 5% and 50%.... ther will give you a  boundary of the unproven technology.

A pleasure

I therefore claim to show, not how men think in myths, but how myths operate in men's minds without their being aware of the fact. Levi-Strauss, Claude