My T/C U-View measure and flask have been very easy to use. MrTom's tip to use dryer sheets to eliminate static is spot-on. I used the U-View measure at the range, starting at 90 grains by volume and moving up 5 grains after 5-shot groups until I found the sweet spot at 110 grains by volume with my favorite bullet/sabot. (I did not pack or shake the charges.) I then used that volume measure at home to average 5 charges on a digital scale at 77.08 grains. I adjusted a Lee Perfect Powder Measure to throw 77 grains by weight; those charges go into plastic tubes for range and field use.
I have a few dozen of the Western brand tubes marketed for BH209 that I use for that purpose (great for storage, but I don't rely on the graduation scales printed on them for anything). If I had it to do over again, I'd save a bunch of money and support a member here by buying Lane's tubes on this site (
https://www.modernmuzzleloader.com/threads/wts-speedloaders-gunpowderstorage-lanes-tubes.24181/).
Finally (and this may explain the differences between my 77.08 grains-by-weight average for 110 grains-by-volume and your 85.6 grains-by-weight average for the same volume), all of my charges are from the same 5-pound jug. And again, I didn't shake or pack my measure in any way - just poured powder to the line. I bought 2 of those 5-pound jugs bearing same lot # at the same time, shortly after Western first offered them, so I'm comfortable sticking with my numbers for now since I still have about half of the second jug left. When those 2 jugs run out, I'll have to start all over based on how much denser your newer sampled Blackhorn seems to be. I've read a few posts on this forum indicating that BH209 has exhibited noticeable density and performance variations, lot to lot, over the years it has been available.