I have a elevated short coop and I HATE IT. Ill never have anything but a walk in coop for the rest of my life.If I were you, I'd use these: https://www.essentialhardware.com/n...qhytVXzyw0xCYUuQrk3-N9zg2y22E9pRoCn38QAvD_BwE
BTW, I looked at the pricing on those Handi-Blocks. That's certainly an error. They are very reasonably priced!!!
When we built our coop, we dug out an area for each block, then laid in a lot of pea stone for leveling and good drainage, and set the block on top. You can then build your flooring directly on top of the block with stringers, or you can insert upright 4 x 4 posts, and attach your floor framing to the posts. Using the 4 x 4 posts makes your leveling job be much more forgiving.
I'm not a fan of the elevated short coops. I'd build a walk in style, and attach the run to that. You can attach the skirt to the floor framing before attaching the siding.
Everything is difficult. Cleaning is so hard, it rarely gets done. I feed inside my coop because rats were eating more food then my chickens. Literally, when I rat proofed, my feed bill went down 70% or so. Even that is difficult.
My chickens like their home but I don't.