I have one of the original 7's with the pencil thin 18" barrel. I haven't worked with it a lot but it isn't a stellar shooter similar to yours. But in the last 30+ years I've shot a LOT of deer with it and so has my daughter. There is no issue taking deer at 200yds with that kind of accuracy.
I use H414 in it, 44gr, 140 ballistic tip for right at 2600fps. If you contact Hodgdon they will give you the temp/fps variations for it. But all powder is subject to temp sensitivity and ranges from about 0.2fps per degree to about 1.5fps per degree with possible variability across the range. In other words, some powders may be consistent across the temp range, others may be consistent up to a certain temp and then become more unstable above it.
Not sure what you have available but you can test it with some ingenuity. I was preparing for an early spring arctic hunt, temps expected around -40F. Was concerned about point of impact and simply if the gun would function. I put gun loaded and all the ammo in my freezer for a few days. Then each morning I'd take it out and fire a single shot at the same 100yd target, load it and put it back in the freezer until the I did it again on another morning. Didn't chrony every morning but a few to see what I got. But I have the luxury that my shooting range starts about 4 steps out my back door. Haven't done it but you could use a hairdryer or maybe the heater in the car to go the other way. I have used the AC in the car for cooling barrels so I didn't need to wait so long between shots.
I use 760 in my 375HH and I think it performs similar to 414. I load it to max and used it in extreme heat in Australia and Africa without issue.
Stand up and be counted, join an outdoor sports organization
Life NRA,Life PTA,Annual SCI