After decades of mostly airline flying, looking to get back into some fun stuff. Spent the last few years slightly getting back into GA in a 172.

Planning on a tailwheel endorsement and a seaplane rating both in a J3 Cub. Never flown a cub, a tailwheel, floats, a tandem plane, or for that matter anything with a center stick.

Does anyone have any thoughts of which order would be more efficient/cost effective to complete both?

It doesn't make any difference. Neither one is about flying the airplane. Conventional gear (tailwheel) is about taxiing, taking off, and landing.

Seaplane is about taxiing, taking off, and landing.

You're already a wheel pilot. You may find it easiest to check out in the cub, then do your float rating, but the two are separate, and independent skills.

Doesn't matter much but I'd say tailwheel first, that gets you back into light airplane handling near/on the surface but it's similar to what you already know. Get handy with the plane first, then go for seaplane.

Thanks, was leaning towards tailwheel first since it’s more local. I’ll knock that one out first.

Have fun! There is nothing better than flying on your personal schedule.

Center stick is sooooo much more natural then a yoke or steering wheel.
You just point it in the desired directions and pitch and roll is much more natural then push-pull and rotate L/R.
Also ergonomically a center stick works much better with how your wrist and elbow and shoulder joints work.
If you’ve got some in the neighborhood fly a Diamond aircraft. Center stick and pushrod control instead of that heinous cable and pulley system that most light GA uses.
I know Diamond aircraft look like a sex toy designed by Mickey Mouse but they fly exceptionally well.

I went with tailwheel first and I’ll use seaplane as a flight review extension later. It didn’t hurt my instructor had a Luscombe.