As for the rest-it's all personal preference and many here have issue with my view on this-but as far as I am concerned-once you add sex to the equation-the probability of building a healthy long term relationship (if you haven't already managed to address that) is reduced exponentially.
That's a individual thing. For some people with sex negative, archaic views, a woman giving up the goods before a certain amount of time means she isn't LTR material. If you want to date sex negative, archaic people then sure, stick the three date plus rule or whatever. If you would prefer not to date such people, and especially if sexual compatibility is very important to you, I'd at least get their thoughts on this sort of thing from the get go. Someone who has those kind of views would not be compatible with me, personally.