Saltwater fly fishing

[Warren]

Having just bought an Alvey 425B fly reel I am keen to get into saltwater fly fishing both estuary and out of a boat (Kingies etc). I wonder if any of you wiser fly fisherpeople could suggest the type of fly line ie. floating intermediate sinking etc. and the best backing. Apparently this reel takes 500 yds of 30 lb Bionic braid which is a bit pricey. Also what is the best type of rod for a beginner (length, action etc.) I can cast a fly for trout etc. but I am still learning the techniques, my distance is not great as yet.
Thanks
Warren.