I'm also chompin to chase the macks on fly. Where? Dog Island Shoal by boat.
My short answer is not around here by kayak, at least to target them. They've been showing up a lot the last 2 years on the flats but they have not been in schools but rather we get one fishing for other things. My favorite answer for them by kayak would be places west starting with Port St Joe. Late March and well into April they are predictable and very accesible by kayak. I'll never forget catching them there 2 at a time (spec rigs) with my daughter on her 2nd birthday, March 24. Negotiating 2 macks at a time with the 2 of us in the kayak was interesting.
"Hey, look at the teeth"!
Closer to here I would think the east end of St George after putting in the bay south from the middle of the park and paddling east to the cut. That's a fine fine bunch of habitat for lots of critters -including spring Pompano. I'm not sure what the paddle is from there to the cut is. I've not done it. That sounds like an excellent group trip. I'm not sure what the park road is like now but the east end is "accessible" by 4 wheel drive.
Chumin? Could be a good idea closer to our area -but maybe not with a kayak. Another version might be to net up a lot of white baits (Pilchards, Jennies, Croakers, Anchovies...), put them in a plastic bag to die

and start chumin at a likely spot with cat food to draw in smaller bait & then start tossing the bigger baits. That's just off the top of my head but it sounds easy, clean & safe.