Just wanted to see what you guys use for a fly leader for Spanish mackerel

https://www.intheriffle.com/store/RIO-Powerflex-Wire-Tippet.html

This works really well. Had a good day last fall catching them on the N. jetty.

Is that where you are headed?

I plan to fish the Port A jetties, the Spanish have been in the bays as our group caught a few Smacks while trout fishing.

typically for smacks you can also use 60-90lb floro instead of wire.

+1 for wire.

rio makes a wire tippet very affordable and in my opinion the best way to go

This.

Yep I use 100 lb on rod and reel because they seem to get spooked on wire especially when they are feeding on glass minnows

If you use an overhand strip and move your fly quickly and continuously you can get away with 30lb fluro or mono. That's what I typically use. If they're really overzealous on a particular day and I get cut off a couple times, I'll move up to 50lb bite tippet. Wire is definitely not necessary and will result in fewer bites. If you're after kings though... gotta either get really lucky or break out the piano wire.