Ed,
In post #13, there is a picture of the valve. As it appears, the full outside diameter of the valve is on top. That is approximately the position you want the valve in at either TDC or BDC. That is, at TDC or BDC you don't want any air to enter the cylinder in either side. Then, adjust the eccentric so that the valve rocks left and right in equal amounts.
An easy way to see what the valve is doing is to mark the end of the valve with a black marker and watch it rock back and forth as you turn the engine over.
Looking forward to your success
Cheers,
Phil