I played Errant at a con last spring, and my recollection is that, of all the systems and subsystems, the only one that was a real bear in play was the inventory/encumbrance system -- it was a monster to track in real time and not a ton of fun. The GM did say that in terms of prep, he found that creating spellcasters and their grimoires or miracles was a massive amount of work. Otherwise, it's only one data point, but it really did play well at the table.
Would you veer towards Freebooters or Errant for a procedure focused (what are Moves if not fiction triggered procedures…) OSR game?