Suggestions for Bi-amping using 440-Pro CI

[audio_engr]

Can you still buy companions? I though that they were removed from the line-up when the CI board was introduced.

The way that I have it is that your options a) b) and c) are therefore all exactly the same. Only difference is that when you buy a 440PRO you get a bit of discount as opposed to buying two separate 220PRO's.

It would be very interesting to determine what the power difference will be should you add another 220PRO to each speaker. Currently each speaker gets 220W into 6ohm which is split between tweeter and bass. If you add another 220PRO, tweeter and bass will still only receive 220W into 6 ohm. The only difference is that each now gets its own 220W rather than sharing the single amp's power.

In reality adding another set of 220PRO's may only add another 10% or so of actual power?

I was told by Devialet engineers (Technical Team for US from France) that I can get hold of 220-Pro CI companions by ordering it thru a dealer who'll then place a request to the Devialet - France factory to deliver the same. Since I am in Washington DC, the easiest way for me would be to place an order with the Devialet Showroom in New York City as they're a Devialet's own establishment in the US but the USA vs. EU price differential is crazy   ...
That forces me to try and find what I want in the EU region (new or used) and get them over to the US. 

Using a 220-Pro CI vs. 220-Pro CI COMPANION is € 1.500 differential I was told.

You wrote : "Currently each speaker gets 220W into 6ohm which is split between tweeter and bass"  
This is not true. The 802 D3's crossover is split as:
Low Frequency (doing Bass) : 2 x 200 mm Woofers
High Frequency (doing Mid & Treble) : 1 x 150 mm Midrange + 1 x 25 mm Tweeter

Since I am bi-wiring the LF & HF using 440-Pro CI, each speaker, i.e. [LF + HF] presently gets 440 watts @ 6 ohms.
When I bi-amp, the LF will get 440 watts & 6 ohms & the HF will also get 440 watts @ 6 ohms. 
Theoretically, it's double the power from bi-wiring but in practical terms, its not .. however each crossover section gets an independent power amp drive with adequate current for it to fully function uncompromised.