Best Center for 4 RC85i

Issa

Hello all,
I'm doing a new install which consists of 4 RC85i in-wall speakers, a Pioneer Elite VSX-32 and (1 or 2)Polk 505(s), (1)Polk PSW111, or/and (1)Acoustech PL-200 sub. My question is what center speaker to get that is not in-wall? Room is 20x15x8.

I'm mostly deciding between the CS20 and CSI A6 but other good recommendations are welcome. I have all of the items except the CSi A6 and curious if that would sound better considering the options.

Naturally, I'm looking for the best possible sound for HT and music and these items. Also, any recommendations for how many and which subs to use?

This is for my g/f's new house.

TIA.

Issa

I know that the CS20 is timber matched to the RC85i's but I do like how the CSi A6 sounds (clearer/less harsh). My question would the overall sound with a CS20 still sound better vs. using a CSi A6 with these in-walls even when both are well EQ'ed?
I'm running two subs with my current system and thinking of adding another. Low frequencies are uni-directional so one shouldn't be able to tell where the subs are located in theory but I can still tell where the subs are and I do like to balance these too just as with regular speakers to spread their sound without needing to turn each one beyond its' sweet spot. I also know that having one excellent sub sounds better than two very good subs in my car but sadly, one excellent sub in a big room is way too expensive and probably would be too large so I have to do with multi good subs. In my car, the sound was better than 90+% of the theaters I've been to and would like to achieve similar (or close) at home and for a reasonable price.
I already went through all the training videos on this site and done a fair amount of reading plus I've been playing with electronics before my teens so I do have some background and I'm an engineer by trade so I'm not a total dunce. I do have room for 3 subs and I'd like to use a free floating center as the TV is 82" (Mitsu 1080p) and will cover the wall to install an in-wall center there.

I know this is subjective but I do like balanced clear sound with the full spectrum and some bass capable.

So, my questions:
1. What better center speaker than the CS20 that I can use with this setup?
2. Which sub or combination of would result in the best overall sound?

This is what I currently have for this install: 4 RC85i's (installed with sound observant behind), CS20, 2 PSW505, BIC PL-200 and a Pioneer VSX-32. I'm using 12AWG cable.

Most likely I'm going to experiment with the subs so Q1 is the main one. My reasoning is that upgrading THE main speaker for HT (the center) will result in the most bang for the buck.

Thanks in advance and any help is greatly appreciated.