Ehhrgg, preemptive strike by CW right when I was marshalling support.
OK, let me stick to the benefits of why one toggle switch is superior to two. I submit there is
never a time that you would want your pushers running and your puller not; thus there is never a need for two switches. Your answer about having the puller off when you're setting the timing didn't make sense. If you're setting your timing with the engine at its normal temp then the thermostatic switch is going to be turning the puller fan on regardless of your switches on your dash. But, assuming,
arguendo, that you really do want the puller fan not running on the rare times you are messing with your timing. Then all I have to do is pull the relay on the firewall and turn my toggle switch on.
Ta Da! I now declare victory and you're just jealous
If you can come up with a reason why two switches is better, or a non-bogus reason why you would want your pushers on and your puller off, please post it -- but keep it polite and on topic so CW doesn't close the thread.