As they say.............been there and done that. I had a Heatmor 200 with shaker grates. I tried bituminous many ways with it and it was inconsistent at best. My best results were obtained by mixing a shovel of coal with the wood on colder days. My recommendation would be to install a coal stoker boiler unless you have convenient access to free wood and don't mind feeding the outside beast twice daily. I had no reservations about selling the Heatmor after using it for 12 years. My wood source was getting farther and farther away from the furnace as I cleaned up the acreage surrounding our house..........and I was not getting any younger. I do not regret purchasing an outside boiler as it paid for itself a few times and kept my mid section more slim and trim than it would have been otherwise. After questioning how much longer I wanted to feed the outdoor boiler and finding this forum, I settled on the EFM 520 as the stoker boiler of my choice and set about refurbishing and installing an EFM 520 with the knowledge gleaned here and have never looked back.
I have that same brand (Royall) of indoor boiler in my shop and it burns bit stoker very well. I burn a little wood in fall until the wood gets buried in snow then switch to coal only. Runs much better on coal than wood once it gets cold out. When its time to refuel just drag some of the burning coal to the front and throw a few shovels of fresh coal to the back 2/3. If you have wood to use up also, just load wood on both sides with coal down the center, the coal will help dry out wet wood so it will burn.
Thanks, That's the experienced feed back I was hoping for! Truthfully : Dry wood is very scarce, 6-8 weeks to go, and I don't want to participate in the "Propane Shakedown" Coal is my best option, maybe forever if I figure it out! Thanks again, Chuck