Dean,
Q1. Should I try to hit the ph of 8.5 before I start the run
Yes, but I am wondering how you are measuring your pH. 10 drops will not produce that high of a pH. I think your meter or test strips are wrong. To move 1 pH, you have to use 10 times as much sodium carbonate, and you cannot be that far off.
Or Will the ph drop as the run goes on leaving me with a lower ph by run end?
The pH will stay about the same
Q2. If my ph is too high by run end can I somehow correct it before adding reducer ?
No, you cannot reduce it except by adding acid which would be a bad thing
Q3. Does a higher ph wreck the batch in some way or does it
Just make it darker?
It might make it less stable over time, but I don't think your pH is that high. I suggest using 10 drops and forget your pH measurement.
Also, I doubt the silver pulsers calibration is correct. Unless using a constant current generator, its extremely difficult to measure the actual ppm of ionic silver. The guy who made it probably stuck a TDS meter in his solution and it read 8 to 10. TDS meters read way low on ionic silver. So you can't accurately know your ppm. Theoretically they should read about half, but I cannot verify that they actually do.
I think you have found that complete reduction of the silver ions takes a little time
This is normal, and hotter makes it go faster.