Thanks for all the responses. Thanks especially to codamedia as those settings worked really well for the amp. This post, along with some YouTube videos I happened to watch, actually pointed me back towards the stock cab. I have definitely been of the opinion that the stock cabs were no good and have been using IR's for years. However, when I started using some real metering from inside my DAW (the multimeter in Logic Pro X) and doing some real deal volume matching, I found they sound way better than I remembered. It's always amazing how much volume differences effect your perception of sounds. The stock HiWatt cab sounds really great. I still really like Redwirez IR's but with their HiWatt cab there is something weird in the sound. It's a mid-range honk like a wah pedal left on to my ears. This was only more apparent to my ears when I dialed in the stock Helix cab and a/b'd it with the Redwirez one.
Anyway, I love lots of other Redwirez IR's and I'm going to definitely give the stock cabs more of a chance in the future. I especially like how you can get multiple dual cab blocks in a preset to blend mics. This is more difficult and processor intensive to accomplish with IR's unless you buy their IR's mixing software.