Methinks you'd be better off e-mailing Broadway Limited on this one.
http://www.broadway-limited.com/customerservice.aspx
Merely inverting the engine may not be enough. It might help to gently shake the engine, but with a hand wrapped in paper towel held over the smoke unit to readily detect if it is worth doing what you are doing.
However, I do agree that a phone call to BLI to ask for some tips is the way to go...just to cover all the bases.
-Crandell
I made a similar mistake of adding too much fluid after I thought the smoke unit might have been defective. Upon emailing BLI they said to just do not add any fluid for awhile, and that the fluid sometimes forms a bubble over the stack which inhibits the smoke from coming out. BMI suggested blowing into the stack to eliminate the bubble. Meanwhile, I discovered that by lightly blowing through the smoke box this will excelerate the dissipation of the fluid. My Hudson is now working satisfactorily, although the smoke is not overly generous.