"not sure where to go from here."
Seems to me your design is getting more and more complicated and expensive!
Fitting a tail, shroud ,switches, motors and possibly a controller of some sort, then it is also going to need a substantial tower to get it into clean air as it will suffer from turbulence at low hieghts just like a hawt does. This is going to cost a fortune.
The most attractive asset of a VAWT that I can see is that it doesn't need to yaw or follow the wind! So surly fitting a tail and duct is a step backwards.
What do you think will happen to your "deflectors" when they get hit by a storm?
The most successful turbines use the KISS approach (keep it simple stupid)
There is a much simpler and cheaper solution to your problems, that will increase the rpm and the output, it will keep the costs down and is proven to work, just build a HAWT you don't need ducts or motors or switches or any other cr*p. The design is very simple with minimal moving parts and is scaleable to suit the output you want it has been well proven and most importantly it works.
I think you will eventually come to see why a 3kw vawt is never going to be practical. You could build a 3kw HAWT for a fraction of your proposed design costs and in a fraction of the time.
Why do commercial wind farms use HAWTs?
Why do they not use ducts ?
When did you last see a successful wind farm use VAWTs ?
If you are looking for a design challenge try and design an improved method for furling a HAWT.
Just the way I see it.
hilltopgrange
"There are none so blind as those, that will not see"