In lieu of a zillion factors...

I have a CK single speed hub and a 19t and a 20t cog. On the crank I can run either a 39 or a 42.

I've never tried to find the magic gear, but is this enough of a selection to find one? I'm looking to run a single speed CX series on a bike with vertical drop outs. I'm much stronger this year, and I'll be far more competitive than on my steel single speeder that I ran last year.

Since I've already got a blingy and expensive back wheel, the old ENO eccentric recommendation is a no-go. And although I like the idea of the EBB30, the customer support from Beer Components has been less-than-woeful (half a dozen e-mails, ranging from informational to courtesy to technical, all unreturned --- BTW, everyone in the world has kids, or a vacation, or a dead Mom, or a dead cat, or a tough life, blah blah, but Bill Gates answers his f###ing phone, just participate in reality and respond, especially if you run a business) and I will never give money to stoners that don't respond to basic communications.

Is magic gearing an art? Not too much in the way of trial and error with only four possible combinations.