Background:I'm converting my hybrid for the road and I'm trying to understand which cassette will suit my needs. I know this is a topic that comes up a lot, but I haven't been able to find the answer appropriate for my setup. A quick nod to one or the other would be hugely appreciated, then I'll hurry back to the hybrid and clyde forums until i'm FAST

Current Setup: 48-36-26, 12-26 9sp....(just bought new 30-39-50)

Current Status and Riding Style: The weird MTB gearing I have now is adequate for the hill in Prospect park, in fact I rarely use my 26 on the front, but I want to ride centuries and I'm hauling some extra weight that many in here might not be. On the other end, I do spin out on the downhill when I reach about 28-30 mph and would love some more pull there. I've been trying to regulate my cadence carefully so I don't want big jumps.

Question: Which 10sp cassette is the best mate for my new 105 (5603) 30-39-50 crank? I don't know how to calculate the range and I'm not sure how important x,y, or z gear is...a 12-27 seems like nice range, but do I really need all that with a triple? 11-25 sounds fun (fast) but will I miss that 16?

Thank you for any comments