DH, we are not connecting because when you ask a question such as "When should I respond back," I don't interpret it as a literal question as I know you are a seasoned DJ here for seven years and the question is extremely fundamental. Accordingly, your "When should I respond" question is interpreted (to me) in a deeper sense to mean "When does 'game' need to be applied in the context of phone courtship?" And thus my response to you.
You text/call back whenever you want to is the answer. You worry about sounding needy. But does not this worry place too much emphasis on HER, and no emphasis on YOU? My questions to you are: 1) When do YOU feel like responding; 2) Why are you so outcome dependent (a/k/a why do you give a fvck so much?)
You countered with, "But game needs to be applied. I just can't call her within two seconds of meeting her as it would seem needy." I disagree wholly. An action--alone--is not the exhibition of neediness. The intent is. If you are needy, then no actions will disguise the sub-communications you promote in person. And if you DGAF, no actions will disguise the sub-communications you promote in person. Sure, texts can be misconstrued, but if she has already met you, then she knows what she is dealing with.
Would it surprise you to know that after my first dates, on at least two dozen occasions, I called the girl within 5-10 minutes of leaving her to schedule a second date! By your reasoning, she would automatically reject me because I look needy, correct? When I ask for the date, I'm in a I-D-G-A-F mindset, l-i-t-e-r-a-l-l-y. So really it doesn't matter when I ask for the date, as long as I ask for it.
Last, I assume the very premise for which you ask this question (as a seasoned DJ) is already a surrender of the frame as you do give a f*ck too much. Resultantly, you are needy, and hence the question. Thus, it doesn't matter when you ask for the date, because there will likely be no second date (unless she's needy herself)!