A point that is commonly overlooked with respect to passive biamping (i.e., biamping without an electronic crossover between the preamp and the power amps) is that both the high frequency amplifier and the low frequency amplifier have to output essentially identical voltages (assuming that differences in their gains are compensated for somehow, which of course is necessary for proper tonal balance), those voltages corresponding to the full frequency range of the signal.
Therefore if the two amps have very different power capabilities, and therefore most likely very different output voltage capabilities, most of the power capability of the high powered amp will not be usable. If the volume control is turned up high enough to use a lot of its power capability the lower powered amp will be driven into clipping, resulting in extremely distorted sound.
In this case you are considering using an 8 watt tube amp in conjunction with an amp that can provide 1000 watts into the speaker's 4 ohm nominal impedance. I doubt that you would ever be able to use more than a tiny fraction of those 1000 watts without clipping the 8 watt amp.
Using an electronic crossover ahead of the amps would resolve that issue in itself, but I would feel pretty certain that you still would not be able to utilize the vast majority of the 1000 watts unless you set the electronic crossover's crossover frequency way too high to be compatible with both the low frequency drivers and the speaker's internal crossover. Also, a good case could be made that having two crossovers, one electronic and one within the speaker, is less than optimal even if their crossover frequencies are set compatibly.
Finally, I see that the Audio Note amp has only one pair of output terminals, rather than providing multiple taps, which leads me to wonder how well it can handle the low impedance of your speakers.
IMO, instead of biamping it would be better to consider just upgrading your amp. Oftentimes simpler is better.