I have noticed some girls become very interested in me during daygame to the point they would agree with me for instant dates. But I don't have time everyday to go for instant dates or stuff so I go for number close but then they flake. So I should strike the iron when it is hot, right? However, for someone who only has 30 minutes everyday for daygame, should I even bother with collecting numbers? I think most hot girls get tons of DMs from guys so maybe that's why most of my numbers flake (only 1 out of 7 numbers went on a date with me). Or do you think it is a self-limiting belief and I should accept the flake rates and still go out and take numbers?
Write a field report. There's a lot of things that factor into this whole question (which has several parts).
First of all, how do you know these girls who flake would be down for an instant date? Maybe you are suggesting it implicitly and then withdrawing it, or just generally making her feel like something is going to happen right away. If you plan on taking the number you have to make some adjustments.
Secondly how are you closing on the phone?
The main two reasons flaking happens ime is a) failing to validate her - meaning that later on she feels that there isn't a reason why you like her except wanting to bang and b) not seeding the date and having her agree to it during the approach.
Ideally (the way I do things at least) toward the end of the approach you remind her why you like her, suggest a date, get a gauge for when she's free and make soft plans, and only then walk off with the number. The way you want it is so texting is just a follow up for what's already been introduced and accepted into the equation.
a) the icebreaker is just a followup reminding her of your name.
b) the texting banter is just a followup for reminding her you're cool and fun (and if you can call back to something that happened that was a highlight of the approach, so much the better).
c) the soft close on text is just a followup for the date you already suggested and she agreed to.
Make it easy for these girls and you won't get flaked on so much.