If you are looking for something to get you started I would go with the IMR. The SSC seems to have lower ES and SD values than the regular 7828 (don't know why) but it is pretty temperature sensitive.
I've started to gather data on the temperature sensitivity and it appears pretty linear so if you know your hunting temp, you can account for it on your first shot. Seems to work fairly well for me.
That being said, I would still like to finish my work up on H1000 as it's more temp stable.