When to get back to profs about funding

[spartacutor]

Hi all, 

I just came back from a visit at one of my top choice schools. It was pretty cool and allowed me to meet up with some interesting faculty. Since I'm a prospective MS student, I fully understand that funding is not guaranteed and I'm trying really hard to get something otherwise I have to say no to grad school.

Anyways I met with a few professors that I thought their research was very interesting and really matched with my interests but I'm not sure on how to proceed next. How soon do you think I should get back to them and simply email them asking them if they could have a position in their lab for me. 

From what everyone has been telling me, it's ok to be persistent but i don't want to hurt my chances by frustrating one of these faculties. 

Thanks for any advice 

[TakeruK]

You can probably do it whenever you want. Since it's the weekend now, why not wait until Monday?