SP's have lives outside of their work so there should be no expectation of immediate replies. In my experience most ladies usually endeavour to reply within 24hrs but there can be all kinds of reasons why it could be longer.
I would wait 2 or 3 days and then follow up once if no reply then I would leave it at that.
I have had people say that they have PM'ed a lady here on LYLA and did not get a reply... ladies don't always check in here daily and also don't always check their work email on days off.
Just my Opinion
