Some results, not quite what I wanted, but I'm learning:

1. Using the Parker Hale sight I was unable to zero the rifle. It shot several inches to the right. Upon reflection, I think this is my fault as I thought I was moving the rear sight to the left, but was actually moving it to the right. Front sight adjustments did not seem to help.
2. You do not want to mount the Parker Hale using a long screw going through the entire receiver. At the extremes of windage adjustment the sight tends to squeeze the receiver restricting bolt travel. A short screw attaching the sight to just the left side of the receiver is likely best. Perhaps this is why the rear sight is attached with a pin rather than a screw.
3. Something that I should of done from the beginning, I need to retest the rifle using the original Mk II rear sight. I also want to try replacing the flip sight with a ladder sight. I have a Long Branch style Mk III on order.

One another note; it is good to stay hydrated. I think the sun was getting to me a bit contributing to me making mistakes.