I just started saltwater flyfishing and got back from Florida fishing for bone fish with a stiffer tropical floating line.

I want to start fishing in the shallow back water flats in New Jersey such as Barnegat and Raritan Bay and understand that I need some sort of sinking line that is less stiff than tropical weather lines.

My questions are:

(1) do I need just a sinking tip or a full sinking line. What speed sinking line do I need? (slow, intermediate or fast)
(2) would I another type of line for surf fishing?
(3) to make things simpler, is there a recommendation for a specific brand and model that you would get as your first cold/salt water line? (I am new to fly fishing in general in the last few months, just learned to double haul, can get about 70 feet or so on the lawn)

Thanks for your responses in advance.