the only advantage is that she may double text you and chase more. But this advantage is that she might find another guy who was messaging her back faster. Generally to me, id rather strike while the iron is hot.

Not really, you shouldn't delay them for more than a couple of days because some girls will either move on or have other plans etc. You don't want to be needy but if you take forever to respond a girl will notice that. In terms of the rules for double texting, normally wait 48-72hrs before reengaging but if she is giving you good engagement and responding relatively quick don't throw that a way by taking a week to respond, 99% of the time it will "turn" the girl off