OP, we're the same height, and the older I get, the more important headroom is. I sail a 27'er and there's room to stand, straight up, right under the hatch, so at least there's somewhere. However, with the head being forward, that's not an option, and for me, I wouldn't spend any "serious" time (read "offshore") in her, as much as I love her.
Headroom never seems like an issue when you first get in the boat, but crossing oceans means weeks aboard, and with each passing day, those "little issues" can become big ones. I wouldn't approach the purchase thinking "I can always stand in the cockpit", because that's not really practical. While not having done it, I do know that rest is key, as the veterans of SN with tell you, and "stretching out" is a factor of quality rest. There's plenty of under 30 footers with headroom, so find the one that works. Good luck and let us know what you decide to buy, remembering of course, pics or didn't happen.