Denon 4520CI + 4806 combo as pre-pro and power amp

I just recently bought an used pair 4520CI+4806 combo which previous owner used as pre-pro/power amp combo. Also, previous owner mentioned that 4806 amp section is better than 4520CI and that's the primary reason for using 4806 as power amp while using 4520CI as pre-pro.

Based on my research, it seemed like 4806 is one of the best Denon amp - beefy amp, power supplies, large capacitor etc. ( other than 5805 of course) and thought it would be great setup as audiophile friend of mine used Denon 4308 as pre-pro with NAD T773 receiver as power amp and NAD has power amp inputs other than regular 8.1 EXT inputs and it sounds great.  Based on checking with my friend, in case of NAD T773 setup, it looks like there is no involvement of volume control on power amp inputs in the receiver but it looks to me that's not the case for 4806 based on looking up online so far.

So here are my questions:

I primarily bought this setup and considering used as I can't afford 7200WA right now but wanted high end sound and that's why purchased used. Secondly, I'm also right now not really interested in setting up Atmos( but 4200W is on fire sale with 5.1.2 setup and is tempting though) for now but at the same time wanted best sound quality for both music and movies. My listening preferences includes 50% music and 50% movies.

1) Is it really worth the pain of setting up 4520CI as pre-pro and 4806 as power amp?

First of all, is this setup really recommended? Also I'm not sure if 4806 really supports power amp mode similar to NAD T773 or not. If it isn't then is this setup really valid/recommended? It's confusing as both are receivers and have volume controls in both 4520CI and 4806.

If this setup is valid, then can you recommend what are the setup steps involved in setting it up in both 4520CI to configure as pre-processor and 4806 as power amp?

2) Secondly, is it going to be any better than what's out there such as Denon X4200W which is on fire sale and also there is a great deal on Denon X6200W

4200 has discrete amplifier and is close to 28 pounds
6200 is close to 30 pounds with mono block power amp construction.
4806 is really heavy around 52 pounds and 4520CI 36 pounds similar to 7200WA with L/R separated mono block power amp construction.
4520CI amp is very similar to 7200WA as both are mono block construction with L/R separated except 7200WA has upgraded DACs

First of all I'm not sure if the amplifier differences between 4520/4806 to 4200/6200 are worth it? I don't really listen at high volumes but at moderate volumes and my speakers are rated 4 ohms.

I did not find really rave reviews on 4520CI other than usual Denon 4.5 stars review from Sound and vision which also provided 4.5 stars for X4200W as well. Does this mean they both perform equally well?

For 4806 there are lot's of good reviews out there raving about sound quality and internals:

https://translate.googleusercontent....Y1dXbr0MnJtbXw

http://www.avrev.com/home-theater-av...eiver-2-2.html

http://hometheaterhifi.com/volume_12...05-part-1.html

Last but not least, I appreciate your help and based on your replies I'll either keep this combo or may want to back out the deal if it's not the right setup as the seller did not provide accurate info on the setup so far and moreover the seller is not going to ship until early next week and I may have to to ask my money for refund(worst case).

Thanks.