What’s the Right Power Amp Ratio For Bi-Amping?

I think the OP is asking about the brain's perception of lower frequencies. If I'm correct what the OP really wants to know is how much more SPL does a low frequency tone require to be perceived as equal to a relatively higher frequency tone. I don't have an answer to that but I've had good luck feeding my lower frequencies around 5x to 8x the watts of the higher ones. I use towers that have an active bass section and dsp. My amp is 50 wpc and the bass is a few hundred wpc. 

Throw a 1,000 wpc x 2 on each side and see if you like it. Buy some old  $300 class D's and see if you are happy. Cost $1,200. 

The question boils down to this: if you had the ability to measure power consumption of white noise (equal amplitude across the audible spectrum, not necessarily 20Hz to 20kHz, if you could do it for 50Hz to 10kHz that would be a sufficient demonstration) by the two halves of a bi-amped speaker, what would you see? 

@vinylfan62, actually, I have bi-amped, in the past (first time in 1972) and currently. It's nice that your Bedini 25/25 (I ran one for years with my old QUAD ESL's) and 100/100 work great for you (knowing Bedini, they probably have the same gain), but the pairing of a 25w amp with a 100w may or may not work with anyone else's loudspeaker. They certainly wouldn't with my Magneplanar Tympani T-IVa's!

I have a B&K Sonata 5ch amp,  150W×5 which I used with an active crossover, it has outboard trim but I used the gain on the X-over to set the levels and the x-over points
That's how it's done in a pro-audio environment (for good reason)
Sounded super clean and strong
I would sell it if you're interested