Bi-Amping McIntosh MC303

I wrote it as bi-amp, my mistake. (i assume I would need a 4 channel amp). I mean bi-wire

How do I bi-wire with the weird setup on the McIntosh

The traditional approach to bi-amp/bi-wiring speakers is to connect the treble and bass to the same impedance tap at the amplifier output. Since the Blade is rated at 4Ω, you can connect both to a 4Ω tap.

You can also experiment by connecting both to 2Ω or 8Ω tap to see which sounds best without damaging the amplifier or speakers.

However, if the speaker treble and bass are connected to different impedance taps of the amplifier, the output levels of the high and low frequencies may be affected.

I use the Kef Blades in a 2 channel system and connect the speaker wires to the 4 ohm taps to my Mc611. The other taps on the back plate of the Mac ampa aren't for multiple speaker wires so much as matching to speaker load. Whatever load you decide sounds connect all the wires to the same ohm output. I wouldn't, personally risk connecting the lower{bass}wires to 4 ohm while connecting the upper to 8 ohm taps.