I don't see anything wrong with that and completely understand your need to do so. But I might suggest doing what I did with my son. I told him he can call, but is not to ask for anything because I will not give it to him. It is real nice hearing from him now, calling just to say hello. Sadly, I can't remember him doing that ever! "Happy birthday Mom, can you give me 10 bucks?"

I am not estranged from my daughter, and she doesn't do facebook. Her husband does. If it weren't for reading his page, I wouldn't know what was going on (as it is, he doesn't say very much). I am grateful for facebook.
So, reading her page is one thing, but if you are going to contact her, I would do it through the private messaging...not on her page- unless it is something like "happy birthday".
(especially since future jobs may also be looking at some point!)
We like to know they are ok.

I can see this is really bothering you and upsetting you. Tough boundaries doesn't mean having no contact. It means taking control of when you do have contact. If she was my daughter, I would have contact with her, insist when we are together she is not using and also keep contact on Facebook.
I agree also letting her know you will not give her any money, but still want to have limited contact.