[G&K] Austria diplomatic marriage. When and to whom?

Just curious as to when is it considered a good time to marry a CS and which ones are least beneficial to marry.

I'm fairly new to CiV and have finally been able to pull off some wins at the prince level. My last two games (Songhai & Celts) have been standard continents maps. I managed a long drawn out scientific win in both of them. In both of those games I was allied with practically all of the CS's. I'm especially addicted to the militaristic ones. Likewise in my current game. I'm not even to turn 70 yet and I'm already allies with a militaristic CS, which also happens to be the closest. I've already gotten an archer and a spear from them. Would you hold out a little while to marry this one?

BTW, my current game is a standard pangea map. I haven't had good luck with those yet.

Thanks...