Dave_72, you do get some advantage from doing biamping (without an electronic crossover, as opposed to running just a single amp) but it is not all that much.
For example, our amps can be monostrapped for more power and in situations where a customer could biamplify passively (IOW using the speaker's own passive internal crossover) universally it has been better to simply monostrap the amps for more power and run them full range. Said another way, the biamplified setup ran a little better than just one amp, but two monstrapped was better yet.
Al pointed out the reason above. If you are not using an electronic crossover, the amps still have to make the voltage (and power), its just used to heat up crossover components.
Tannoys are pretty efficient anyway- I think 96-97 is typical. So if you have 60 watts available in most rooms that is unlimited power.