Use the statistics for a crawling hand (Pathfinder RPG Bestiary 2 59) to represent the detached hand, save that the hand isn’t undead, doesn’t have the mark quarry ability, and shares your alignment
There are two Crawling hand creatures, the Crawling Hand CR 1/2, and the Giant Crawling Hand CR 5. both are found in Pathfinder RPG Bestiary 2 59 and both have crawling hand in the name, but only the Giant Crawling Hand CR 5 had the mark quarry ability to be removed.
So can you use the Giant Crawling Hand CR 5 with the feat, the idea being that when you remove your hand it grows to medium size.
Looks like the Archives are wrong on this one. They both have the Mark Quarry ability. It could be that this was originally an error, and the Archives simply never updated when the errata came out.
You are intended to use the diminutive version of Crawling Hand.