Good luck down there, a little tan gotcha with a little flash if my memory serves me right. Beautiful sand flats at the right tides. I didn't see any shoals of fish but they were tailing and pushing water at low light and cruising mid-day. I mostly saw small groups of big fish while on the Keys. I'd recommend renting the kayak for transportation or focusing on the darker flats to the south near the waterfront campsites with a brown fly.
Tarpon exploded on pilchards while I was there too, but I didn't make a cast with my little bonefish fly and light rod. I didn't feel like losing my flyline.
Lots of nurse sharks around the rocks on the north end of the park. Kayak around to the backside if you have time, best bones over there but remember to wear very good footwear and shuffle, not step.
The Matecumbe fish was on a small fabric crab plopped into the sandy patches between broken coral. It was frustrating trying to pick the patch the fish would swim over, then I finally got lucky and the fish swam right into the clear spot I had the fly in.