Sorry to say this, but the D810(a) is not a good match with the SGP autofocus routine.....
The first exposure took a couple of minutes(!) to take & proces. Not usable.....
I had a (cloudless) timespan of 30 minutes to get it all set up with the FSQ. It was hard to get the proper backfocus distance with an OAG, so I never had a chance to finish the routine.
I noticed the same when I went to Namibia earlier this year with a D810a & a Star 71 APO, so I only used SGP for its sequence. No autofocus and/or platesolving.
The D810a is a superb camera though!
I have an old laptop for SGP to use, but even with a SXV H35 (11k. fullframe ccd) autofocus was possible. (7 point routine in 4 minutes or so)
Regards,
Marco