I use a Calcutta CT 200 B for my Fall fishing since I'm targeting coho and it is a SWEET reel! I also use a Luna 253, which is probably similar in size to a 300 and it too is a great reel. Personally, I prefer the 200 B because I like the smaller size. I've never had a problem on local rivers like the Vedder/Chilliwack with braking or line capacity, and I do hook and land the odd spring. If I was specifically targeting larger salmon like springs and chum (which I don't, unless it's for the summer red Chinook), then I'd lean toward the larger 300 size reel. In fact, I've got an Abu C3 5500 with upgraded ceramic ABEC 7 bearings that I specifically use for red springs - but that's another story...
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As for the Calcutta 400 series (or Abu 6000 series), these reels are too large for smaller systems like the Vedder/Chilliwack, but suitable for the Fraser.
So - I guess the question for you is what do you want to use this reel for? Are you primarily targeting coho, or are you intending to target springs on a regular basis as well?