Marshall, good points! I always tell my students that one of the obvious cons of sup is going upwind. But there are ways to make it work even in strong wind.
- tacking works as you found out but does require more paddling. Another similar version is to paddle in a staggered foot stance paddling straight. This rotates your body somewhat reducing windage. Take some practice for some in having a foot behind. Which foot behind? Whichever feels best behind you (or you'd fall back on, a good test).
- Short cadence removing the paddle at your toes, using as much upper body as possible (straightish arms). Every time you return your paddle to the catch the board slows -reduce this time. Also called the Tahitian stroke used for racing.
- Paddle on one side. 2 ways: push one rail into the water a bit and paddle on that side. adjust your trim on the board to find a sweet spot where it works - doesn't do as well on shorter boards or with a lot of rocker. 2nd type - canted stroke, basicaly a j-stroke - pulling in from beyond the nose and straightening to the rail, can be tiresome though.
- use eddies or small bays or points offering wind protection to go upwind. may sound like a longer paddle but more efficient than going straight against the wind. docks offer protection too.
- feather your blade, even in non wind situations. this really helps. keep the blade close to the water as you return to the catch.
- worse case, if going upwind not for fitness - sit! kneeling is popular but you're still not as efficient as sitting. choke up on the paddle shaft, use a torso only stroke (think canoe or outrigger stroke). Also prone padding is the most efficient way to go upwind but exhausting if you're not used to it.
- more expensive route - get a pointy nosed board or even better one with a point and vee in the hull also called 'displacement' in sup terms. way more efficient than a round nosed board.
around here, upwinders are rewarded by downwinders. i tell my race sup students to practice paddling upwind not only for fitness buy also in case the race ends up being an upwinder. paddling upcurrent is wise too in rivers or tidal rapids.
hope that helps.. :)