Does your 1500 have the hopper? Mine does, and even on the coldest days of winter, with the stove top temps flirting with 600F, it will just barely empty the hopper in 12 hours time. The firebox will still be full of hot coal.
With a non-hopper model, I could see having the more frequest tendings. If that's the case, I would make sure you're filling it to the top of the firebrick, and pile it up even higher towards the center.
This past year, at the end of the heating season, it only took 15-20 lbs of coal in a 24 hour period.
I'm running just an MPD, don't have a baro. I don't think it's needed, since the bi-metal t-stat regulates the air coming into the stove.