Forget about the rocker ratio, it is totally insignificant. Measuring at the retainer all you want to do is make sure whatever reading you take on the upstroke is the same on the downstroke. So, if you use .075 on the upstroke, use .075 on the downstroke.

Now, since all this is dependent on an accurate TDC, how did you do that with the heads on?

And if you're checking at the retainer, make damn sure the shafts are bolted down tight.