Weight, or mass, isn't everything. In fact, you could make a similar argument over rods! The Calcutta 200B is a smaller reel with higher precision, and will toss out lighter lines and lighter weights much more efficiently than the C3 6500. Think about it. The mechanics are different between the two reels. When you cast a 200B, the levelwind does not move because the spool isn't as wide. This results in a smoother cast, particularly with long distances and light weights, and the reel free spools with ease. Contrast this to a 6500 - the spool is wider, the line guide moves back and forth during the cast - more movement and friction in the reel during the cast = less smooth.
I line my reels as follows:
Calcutta 200B - 10 lb. maxima ultragreen - great for small flows and coho
Luna 253 - 12 lb. maxima ultragreen - my coho/steelhead set-up
My Abu C3 6500 is currently set up with braided line and I use it for bigger flows. Don't get me wrong. I love my C3 - it's a classic. In fact, I've "hot-rodded" this reel, and it's a beauty!
As for the 200B vs. the Luna 253, it's a toss up. I do find that the Luna anti-reverse bearing (roller clutch bearing) started to fail when the weather got really cold, or if any sand or grit got into the reel. I was surprised by this, as I take good care of my gear and never lay it down in the water or on sand/gravel. I had to take the reel apart and clean the ARB, but once I did that the reel worked like it came out of the factory. The Luna is fully machined, and is a very nice reel indeed. The mechanics are similar to the 200B (i.e. no line guide movement on the cast). To be honest, I love them both.
I haven't used a Currado, so I can't comment on it. Anyway, that's my 50 cents worth! Either way, you've got a primo set-up for coho/steelhead!!!