Optimizing McIntosh 7300s as monoblocks

I have been lucky enough to find 2 MC7300s to drive a pair of Cello Strad Premieres in a BIG room. Can anyone tell me the best way to connect the tri-wire Cello Strings to the amp taps? They are bridged and using just the 4 ohm taps, as recommended, isn't cutting it. Is it risky to use the 2 ohm taps (remember: bridged, thats 2+2=4, and 4 is the minimal impedance of the Cellos). 6 is nominal. So should I use the 2 ohm taps for bass and the 4 ohm taps for mid and high?

Thanks one mil...

Go ahead and try the 2-ohm taps, you won't hurt a thing. In this case, you will actually be drawing less current from the output stage, so the amp will breathe easier. Even if you were going the other way . . . well, Mac amps are pretty hard to blow up.

Also, some Macs had an option to parallel the outputs for mono as an alternative to bridging them . . . I can't remember whether the 7300 is one of them. Not that doing this is necessarily better, but maybe one more thing to try.
Went with the 2 ohm taps and found a lot more room. So I'll probably go ahead and just experiment with using the 2 ohms for bass and the 4 ohms for high & mid, one reason being I'd like to connect (triwire) all three pairs of speaker terminals to the amp with the Cello Strings (the Mac binding posts barely let me squeeze 2 spades onto a tap). But...

Should the bass get the lower impedance or should the high & mids? While the bass demands the most, lower impedance doesn't equal power so much as headroom, right? At 4 ohms, the bass seems looser while the highs and mids are walking around like they own the place. This may all be due to new interconnect config, so......
The output taps are very similar to the gear ratios on your auto transmission . . . in this case, how fast you can go depends on the balance of how high the engine redline is, and how steep a hill you're going up.

If you correlate maximum audio power to maximum vehicle speed, then the amplifier's internal power-supply voltage is like the engine redline, and how steep the hill is correlates to how much current the speaker is drawing (the impedance). The usual penalty for "lugging the engine" (being on a higher-impedance amplifier tap) is an increase in distortion, and sometimes a modification of bandwidth and transient response. The penalty for being on a lower-impedance tap is a reduction in gain and power output, but if the amp is operating in a more linear fashion, it may still sound more powerful.

While I'm not familiar with the Cellos in particular, most dynamic speakers require more current (and power) in the bass range. The only thing to keep in mind if you're going to use different amplifier taps for the bass and mids/highs is that the gain will be different, so you'll have to turn down the mid/high amp a bit to get the same balance.

Also, you shouldn't use more than one tap on a single amplifier channel at one time. While there are some hypothetical situations where this could kinda work, it will most likely cause a very demanding load on the amplifier, and adversely affect the damping/HF performance of the output transformer/autoformer.