Yes, I'm really going for ballpark, but I thought I could narrow it down and get close.
I made an error in last line of calculation.
So if I subtract 6 turns (3.5"), floor to top w/w. stock should be 30" (33.5" - 3.5")
But since my tires are 1.9" taller than stock (31.5" vs. 29.6") my "stock" height with the 285/60s should be 1/2" less (1.9"/2), so floor to top w/w = 33"
should read - should be 1/2 the total - so 1" instead of 2" (not 1/2" less)
So, 30" + 1" = 31" floor to top w/w.
BUT
Now you confirm 6 turns did NOT equal 3.5" lift -->I now realize I should have divided the 3.5" by half -- 1.75" PERFECT- that's what your real world calc came to. 
I want it to come down about 1", so I think about 2 turns should bring it down to "about" stock. DONE! 
What have I learned
----> don't try to do TB and tire size calculations after enjoying a few brewskis!

Thanks for your help!