I have the Brasslite Turbo, and it works well for me.
As for your specifics:
) Is it worth while to get the stainless steel stand extensions?
Probably not needed...I don't use them.
2) What would the best size plus material to use for a wind screen.
Heavy duty tinfoil. Take a sheet, fold in half, and then fold to make a pentahedron or hexahedron which will fit around your pot. One sheet will last for multiple trips if you use a little care..
3) What size pot would allow me to store the brasslite plus the windscreen inside?
I just recently bought a Ti pot, from MountainGear. I can't remember exactly which one (and its not handy) but it was about 4" in diameter, and ~4" high. The brasslite fits perfectly inside.
I haven't tried to use the simmer ring, BTW....just pour the fuel in and go. Used it in cold weather (~40 F) with rain/sleet/snow in Kings Canyon, with no issues.