It's like the old saying, sometimes you have to kiss a bunch of frogs to find your prince, or whatever analogy of saying you want to use.
Dating, whether online or any other way is a matter of process of elimination.
You will have to go through some frustration to find the right person.
I'd say forget about asking what the schedule is like, as some women may take this as being a bit to lacking in assertiveness.
Instead, perhaps say something along the lines of, "I was thinking of going out for a lunch/dinner/drinks/ or a movie on Saturday/Sunday, or whenever - would you like to catch up? - If so what time would suit?"
Potential partners are looking for someone assertive and decisive, and unfortunately when you try to be accommodating and consultative when it comes to arranging a date, it can be seen as being a bit ambiguous, or lacking in commitment.
By the same token, be picky about who you ask out on a date, even if you have been corresponding a bit.
I met my wife on an online dating site, and we emailed, messaged, and phoned each other for days before we met, and met at a mutually convenient place near my work after I finished a shift.
It can be done, and it can be worthwhile, but you need to find the balance between being assertive, being interested, and being communicative.
It's not easy, but if you find the right person it may be worthwhile.