...and everyone else who provides advice on these forums. Have only been in the Kgirl scene here for 1-2 months, but y'all have made it much easier to crack and understand.
I have used CDL's tip in "how to text bookers" he's provided on earlier threads to much success.
To answer OPs question re: how long does it take for bookers to respond, in my short experience, it just really depends.
Some never respond, though I provide the correct info in the original text (name/age/race/maybe job [only if prompted and has only happened once], date/time of appt request with specific girl + CDL's "open to other girls" statement, 2-3+ recent Kgirl references, etc). Maybe the girls aren't taking new customers/don't like my references or they can't verify them/whatever. No big deal, try again later (the persistence part) and/or just move on.
Some respond immediately, some take a few hours. Never had one take longer than a few hours so far, if that happens, I generally don't get any response from them.
Some only want same day appointments and advise you to contact them at 9am the day of (not sure if I build more credibility over time with them they'll allow more advance appts), others let me schedule an appt many days in advance right from the get go.