Re: Sighting in scope questions.
I shoot 80 to 100 yards on a regular basis, but in order to do so with any consistent accuracy I use the HHA Optimizer Speed Dial and a variable 3 X 12 power compact scope mounted on the HHA Optimizer.
At 100 yards I'm shooting at 8X on my scope. If using a variable power scope you need to insure you have the Parallax setting adjusted correctly or your groups will open up and spread out beyond 6" to 8".
I would recommend making sure your arrows are each matched for spine and weight before attempting these type of yardages. Mismatched spines will surely affect your windage and mismatched arrow weight will affect your elevation by minimally several inches at this distance. The stock factory 85 grain field points are way off the 85 grain weight if you use an electronic grain scale and are measuring to the tenth of a grain. Also make sure you number your arrows before starting, so you can accurately know which arrow hit exactly where based on your firing order. You won't be able to see them unless you walk up to the target following each shot.
Sometimes by first weighing your points and then shifting which point you place on which arrow, you can get them much closer to all weighing the same. two or three tenths of deviation between your heaviest and lightest arrow should be close enough to remain consistent at this distance.