Welcome back!
At the moment there is no feature that allows you to hide Google Translate/Microsoft Translator suggestions. You could try using your CSS to hide them, or write on Support requesting a gadget for it.
If the translators don't know how to use the provided tools, they must learn it or go elsewhere.
However since you are offering money , some anonymous/money-interested users may be temptated by clicking a few hundred times on false/approximate translations and decrease your translations standards.
I also will be the first to "go elsewhere" if working hard on weekends to find the accurate translation and days after see some hobby translator changing it to the stupid Google/Microsoft translation with a simple click !
It was just a proposal.
Cheers