Hi,
There have been several 5.1 implementations in a room of your size so don't worry. Important thing is acoustics. Try covering the open 3rd side (Dining area) with a heavy curtain. It would make a lot of difference to the sound. Carpets and furniture also do a good job!
Coming to equipment, RX6 are very good speakers with deep bass but obviously a subwoofer would give better effect. It is usually preferable that the front 3 speakers are of the same make for timbre matching so have the budget for the RX Centre too. The best amplifier to drive the RX6s in my opinion is a Marantz SR7007, Denon 3313 but a SR6007 should also be a good option. I had experienced RX6s with both a 2113 and a 3313 and could see a lot of difference. Coming to the Subwoofer, you could go for Velodyne Impact series 10" or even the Dali Sub E-12F or even the polk subwoofers. As for surround you can try the Wharfedale DFS which are decent dipole speakers.
The onboard room correction on the receivers should reasonable be able to adjust the sound in your room!
There have been several 5.1 implementations in a room of your size so don't worry. Important thing is acoustics. Try covering the open 3rd side (Dining area) with a heavy curtain. It would make a lot of difference to the sound. Carpets and furniture also do a good job!
Coming to equipment, RX6 are very good speakers with deep bass but obviously a subwoofer would give better effect. It is usually preferable that the front 3 speakers are of the same make for timbre matching so have the budget for the RX Centre too. The best amplifier to drive the RX6s in my opinion is a Marantz SR7007, Denon 3313 but a SR6007 should also be a good option. I had experienced RX6s with both a 2113 and a 3313 and could see a lot of difference. Coming to the Subwoofer, you could go for Velodyne Impact series 10" or even the Dali Sub E-12F or even the polk subwoofers. As for surround you can try the Wharfedale DFS which are decent dipole speakers.
The onboard room correction on the receivers should reasonable be able to adjust the sound in your room!