You should have all your documents together and included in the application before you hit "submit." This is the case for any visa, I would imagine. Sometimes you can upload supplemental documents later, but there's no such thing as "pretty much granted" if the application doesn't include all required documents. If it's listed as a requirement, make sure you have it attached.
This means you will need to be fully invested in the process, there's no "testing the waters" before going ahead and getting your medicals etc.
My first step would be making sure that experience and job type were likely to get an approval, maybe others can advise on that aspect.