I personally would go for the first option- gives him a bit more flexibility in reply and is a bit softer overall.
I like the planned response to his text- how nice of him to remember that you were playing and contact you about it. You must have been on his mind.....
I wish I had advice on a long term strategy. I think so far that what you're doing seems to be working- would you say that you and B have a good friendship at the moment? If so maybe start injecting a bit of flirtation? Have I said that before? Or maybe I was just saying it to myself. Anyway, IMHO if you have a solid friendship going I think injecting a bit of non-verbal flirting could be a good option next time you see him, or maybe say something a little unexpected in a text/e-mail and see what happens...
