I think it is best to start at the top. If you clean as you go then you only have to clean once (basically). This is not to say only one cleaning is necessary.In which direction should I grout walls: from a floor up to a ceiling or from a ceiling down to a floor?
Not really, this is why you start at the top.Is there a way to prevent grout from falling down to a floor while I am spreading it on a wall?
Yes, this is exactly that I noticed.It's a learning curve----unsanded tends to thicken up as it slakes.(sits for a few minutes)
Yes, this is exactly that I noticed.
After I mixed and applied unsanded grout already 5 times during last 3 days I learned to which consistency I need to mix it and how to apply it in order to prevent most of it falling down from walls during grouting.