Thankyou both. I just ordered a box of the .400 185 grain CF and a box of those .400 215 grain CF. I also ordered the H4540B sabots from Harvester and the Tan MMP's. Not sure those MMP's will hold up at all. Funny that they don't make the HP for .45 barrels. I also went ahead and ordered another sizing die from Swinglock for smooth sizing the .451-.452 bullets.
Now one thing I do remember is the old man using sub bases sometimes for his land riding bullets in his Thompson center barrel. It seems they don't make them, or I can't find them, in .45 so I guess I'll have to do some cut down versions from some .45 sabots. Unless you guys think I would be better served with the cushion of a veggie wad. Just makes sense that a sub base would be better at pressure transfer and sealing the bore.
GM54-120, from those traces you posted, it does seem I would be best served with N120. I have a pound or 2 so I'll give that a swing. If you remember, I was going to use that as a booster in a duplex load. Looks like it has a little more power than the 4198 I was using with those 300 grain Noslers. Thanks again for those traces.