Question on using bi-amp...

If I understand your message correctly, you are not trying to biamp in the normal sense but instead, you are trying to connect both amps to the same set of speaker terminals such that you can switch amp at will (base on the kind of music you want to play I presume). I strongly suggest against it because if you forget to turn off one amp before turning the other one on, you will fire both amps and your speakers. Even the amp is turned off, it will definitly have ill effect to the other amp and to the sound in general.

Don't do it.

yes Sidssp.that is exactly what i want to do.and sometimes i rather use a SS then tube on a certain hotday and try to find a quickest way to un hook all the connects from 1 amp and re-hook it on another..i guess,there is no easy way..thanks

Yes you can do it,that what the way I did for my system and
it wont hurt your speakers either.

If you connect both amps to the same terminals at the same time, you are courting disaster.

connecting two amps to one same terminal will result in frying one of the amps or even both depending on which one is on. In my VTL MB100 the output impedance is 0.3Ohm that means that if I would connect it along with the other amp(some of them have even lower output impedance) the resulting load on each amp will be almost zero which certainly will result either blowing of an output fuse or even output transformer. you should definitely use an A/B switch and please do not call it bi-amping. now having a tube amp you must realize that if you leave it on without loading unswitching A/B switch you will fry the transformer so you should arrange a dummy load resistor while one of the amps are not operating but stays on(would you turn-off tube amp every time??)
as far as I know that your bat can be re-arranged as mono and you can buy the other same bat. many people have done this so far and have a great improvement in performance of 120W per each side.