Admired the 243 Rockchucker from a far. Love the 6.5-284. Never tried the 6-284, but bet it is a killer round, as I love its brother.
These are pretty hefty loads for strictly varmints, IMO, but really depends if you are looking at really LR shooting of these critters. How big are these "varmints" that you are planning to explode? I don't think that I would want to spend the entire day blasting away at a PD town with any of them myself