I couldn't do ongoing long emails & IM type chatting in these instances. It can prove a colossal waste of time (literally) as meeting the indiv. in person is most often a completely different experience.
I would do about 3 email exchanges, and always at least two phone calls. Much more can be gaged there than in email. The men would give me their numbers & I would use call block when I called them so they would not see mine. The emails & phone conversations were all info. points in whether I actually still wanted to meet in person (as I'm sure it was the same for them). Most of the time I did, but in talking with some on the phone it became apparent where it didn't via email only, that we wouldn't be a match, so communication (kindly) stopped there, before even meeting.
The whole process from first contact to meeting in person was never longer than 2 weeks. Keeping in mind that emails & calls were sporadic, with several days of no contact in-between.
It think it's good to meet fairly quickly to see if there is any in-person romantic chemistry. So many times people have such a wonderful rapport online & via the phone, and this does not necessarily translate in mutual physical attraction in "real life". I have seen people spend months before meeting, and so much of their emotional energy & hopes get tied up in the whole thing. Then, it is really hurtful to all when they meet & there is no chemistry after all of that. It actually can feel like the end of a relationship in the true sense.
And once you meet you can always go back to emailing & calling for a bit to get to know one another within more if wanted, before a longer second meeting. At least this way, all the while you are communicating online/phone you both are very aware of what chemistry you may or may not have, & can interact accordingly...