dynuaudio c-1s in a small 10x12 room?/amppower?

In your case - C1s in a small room - there would be a problem, because they require placement away from the walls, especially from the back wall, because they have a rear bass-reflex port (I can afford this in my room, which measures 12 x 16,7). Therefore, I would recommend some fine monitors with front bass-reflex port. And do not exaggerate with the amplifier's power, 250 W/8 Ohms from A 21 is far enough (I run my C1s with 2 x 200 W/8 Ohms amplifier).

IMO,your room size is tough for the C1s to shine(small and almost square)Been there done that in a similar room.Room treatment will be a must.If you dont already own Parasound walk away from the table..I would suggest Pass labs X150.5,with the extra cash buy a nice sub and treat that room

I had the C1's in an 11 x 13 room with both the boulder 800 and 1000 series amps. The 1000 series was able to control the low frequencies much better than the lower powered 865. Your problem is going to be in the low/mid bass overloading that room. I had tons of bass traps in there and it still was bloated and overloaded. IMO, the problem is the rear facing port in a small room. I now have a sealed speaker and my mid-bass problems have been solved while actually getting "deeper" extension. I used an RTA and if I remember correctly the hump was at about 65 htz. That being said, the C1's are still awesome and some days I regret selling them. I had mine about 3ft from the front wall, approx 6ft. apart with moderate toe in.

there is no way you are going to need a sub.............

You will be just fine in a room of that size. Even though they are rear ported, you can put a c1 within 6-10" or so of the wall and still get great sound. If you get too much bass, but a foam plug in the port. You will likely need to do this.

Amps: I would go for something more along the lines of a nice high quality 50-100 watt ss amplifier or better yet a tube amplifier. In general low powered quality ss amps tend to be a little sweeter than high powered. The lower power in your room will result in less authoritative bass, which will help with the small room. A tube amp is great with C1's because tube amps have wonderful low level resolution and the C1's Esotar tweeter will show this off quite nicely.

Disclaimer: I have financial ties to av industry.