Flyfishing in saltwater is very hard on your equipment, therefore I would start with a reel that is machined from solid bar stock aluminum. Most manufacturers use aircraft grade aluminum. Next, I would recommend that the reel be a large arbor reel. I recommend this for two reasons. One, with a large arbor reel you have faster line retrieval when fighting bigger fish; two, with a large arbor reel the fly line will have less memory than with a small arbor, and your line will not look like a spring laying on the deck of the boat. Next, the reel needs to hold at least 200 yards of backing for bonefish and permit and for those bigger more determined fish that you might encounter, 300 yards is the minimum.