Don't you think that you're going to need to load for the temperature range most prevalent in your area or that will likely occur in a shooting season of matches? Current thinking--according to this forum --is that a temperature difference of 20 degrees Fahrenheit will require a change in the powder charge and/or bullet weight.
With that in mind, I don't bother trying new loads here when the temperature is -- as it is currently-- an arctic high in the 20's, when I know I will be shooting at a mean temperature of 50 degrees F the bulk of the year. When I lived in PHX I was crazy and shot in temps from 60 to 110, so I had to do a lot of experimenting, but it seemed like a load dialed in at 75 or so would work well most of the year. Of course, back then we figured a temp under 60 was too cold to leave the house and the heater and the beer, and etc.... OK, at the time I had other priorities besides shooting.........blasphemy, I know............
BTW, I shoot a lot of .223 besides the BR calibers and it does not seem to be terrifically temperature sensitive when using N135 sas some other rounds might be. A fairly heavy load of N135 behind a medium weight bullet in a medium twist rate barrel seems to be a pretty good all weather round up here, at least for me.
You probably will find more people on the factory/hybrid forum shooting this cartridge-- hence more input.