I think that I've seen you say several times about "Not" zeroing @ ranges over 100…..
I can agree……somewhat! Here's what I do, tell me where I'm in error!
I do my initial load development @ 100 yards. If the load looks promising…..I then shoot that load at 300 yards (my home range maximum). In my mind, this will "help" determine the loads long range potential! I also zero @ 300…..a distance decided upon long before we purchased a range finder.
You mentioned, environmental as a zeroing issue. With having a backyard range…..We have the opportunity to do our range work, load development and zeroing during absolute perfect conditions. If less than perfect conditions….we have dozens of other things to do around the place! In my thought process, "IF" we can shoot good groups at 300 and adjust accordingly, I think that there will be "less" error at longer ranges than with the 100 yard zero!