I haven't used that particular spray. Of the ones I have tried, I prefer 505.
Definitely protect your floor with a sheet. You can toss the sheet in the laundry. Can't do that with a floor!
It's a good idea to let your quilt sandwich dry for 24 hours before sewing. Although I don't have to do that with 505, some sprays do need that drying time in order not to gum up your needle.
Here is a good tutorial on the process. It helps to mark centers on all sides before layering (folds make a good mark, as do pins) so each layer is lined up with the preceding layer. Also it is important to fold back layers and spray only a section at a time. Here is the link with good photos:
http://thecraftyquilter.com/2012/03/...te-your-quilt/
Edit: I see she doesn't protect her hardwood floor. That's because she knows to always spray from the side towards the center. If you use a sheet as a protector, I would tape the corners to the floor to prevent it shifting while you work. Painter's tape is very good - non-damaging and will not leave adhesive behind (as long as you don't leave it in place for months).