I just found this thread through a search and thought I'd answer some of the questions raised in the original post. (This is just for future visitors to this thread who might have the same questions.)
The California Air Tools 365B 5-gallon pressure pot has a flat bottom. It is 11" deep.
The paint auger is removed by loosening an allen screw in the collet on the top of the lid that supports the shaft of the paint auger. Once the screw is loosened, the collet can be removed and the shaft of the auger slid through the bottom of the lid. The hole left by the auger is 5/8" in diameter and can be plugged with a 5/8" bolt of the appropriate length, a couple of neoprene washers, two wide fender washers, and a nut. Very simple.
Other than removing the auger, the only other thing needing to be done is to remove the paint draw tube. That's done with a pip wrench or vice grips.
The pressure pot is a beast! If you don't mount it permanently to your bench, you'll definitely want to use the included casters.
Not asked: Why buy this pot rather than the much cheaper (and less expensive) HF? My reason is that I wanted the greater capacity for larger castings. Normally, I won't be using that capacity and the HF pot would suffice. But, when I wanted the larger capacity the HF wouldn't do.
Another reason is safety. Assume, for the sake of discussion, that both pots are made to the same standard of quality. Still, the HF is rated for a max pressure of 60 lbs. The California Air Tools pot is rated higher -- mine is rated at 90 lbs. (California Air Tools has made different versions of their pot over the years. Some are rated at 80 lbs.) So, say you're comfortable running your pot at 50 lbs of pressure and get good results with your castings. Great, with the HF pot you'd have 10 lbs of safety 'headroom'. With the California Air Tools pot, you'd have 30 - 40 lbs of safety margin.
And, if you think that your casting would be improved if you could use 60 - 70 lbs of pressure, the HF isn't really an option. At least, not a safe option.
