sounds about right. I use the short metal cages, I will be interesting to see how long one lasts me. I think they each hold just under a FC, so you saying that 4 equals a cord seems about right to me.
I attached a picture of the load I put in at 230pm yesterday afternoon. This load consisted of 50% seasoned oak/cherry and 50% green slab oak. That big hunk of wet oak in the middle was a monster. weighed about 50lbs. doesn't look as big in the pic. Anyways, this load lasted me until 530am this morning. so 15hrs give or take. it was down into the teens last night and I live on a hill where the winds are out of control. Last night I was heating 4400sqft. 3400 sqft house (good insulation 2 x 6 construction built in 2005) at 70, 400sqft at 75 (puppy whelping room, spray foamed and r30 in the ceiling) and 600sqft shop at 45 (shop has no insulation in the ceiling, haven't gotten around to it yet. on a cold night from keeping an eye on the digital temps sensors in the house I figure the 100k btu heat exchanger in the shop runs on average of 25-30min per hour). There wasn't much left but a light coal bed, but I was happy! I placed a nice split over the nozzle, packed the little remaining ash/coal mix around that spit and stacked her up good with the same seasoned/green slab mix. so far it is working right. still getting used to heat load and wood needed tho, it will take a month or so for me to get it down right and proper.