That's indeed a good question. If you play it in Japanese, then I would say you should play the 1st one and then you should make a break for about 2 months or so, then you don't have to wait that long for the last one. If you want to play the 1st one in English, like me, then you have to wait anyway, and I think they will finish the translation around February, which means that I can play the 1st and 2nd one one after the other and then I have to wait a little bit for the 3rd one. But I don't know yet how much time I'll have, maybe I'll just play it after school anyway, which would be around June :D
About Boob Wars: The nonexisting plot isn't the reason. It's more the characters which are the reason for it being so bad in my opinion. I mean, you have to read 5-10min, then a card battle and then a hscene. You only need about 8h to complete all routes and there's no character development.
Btw, have you played Coμ - Kuroi Ryuu to Yasashii Oukoku - so far? Put it on my list, but since there's the "One True End" tag, I somehow have the feeling that it's a depressive one.