Good luck with that. I'd go with the looser soil. This selection develops thick roots that may be able to tolerate heavy soil. It does not like being pot bound, so hopefully, there are cracks in the soil for it to run.

The first 6 inches were soft limestone rubble chunks and some soil., but after that it is a hard limestone. I dug a square 24''x 24"x 8" hole. I piled up the rock chunks elsewhere where I will use it and some boulders to plant a beavertail opuntia. I filled the hole with a sandy/composty mix and added in some of the native soil. This is very friable. I can break up the soil around it too. and add in more garden soil. I should be building a bed but I am a cheapskate by neccesity right now. Other plants (fragrant mimosa,Live oak) have ran their roots through the top rubble layer. I could mound it up above the hole more also.