Ok so here's the breakdown....I took the RJ (no choil/ricasso), a Stretch (for choil comparison) and an Endura (for ricasso only comparison) and I opened them up until their respectives "stops" hit my finger, and then I moved my finger back while closing the blade further and further until the edge hit my finger, which would be the furthest back that a person could position their finger before getting cut (or up to the point of actually getting cut. This distance may vary if your finger is thicker or skinnier than mine but here's what I got:
After doing that with each knife I set them down on the table and lined them up, here's how they compare:
Now I didn't micrometer those but they look pretty dang close to me. What this ultimately means is, if you manage to position your finger back to a point that the RJ cuts you, those other knives would have also cut you.
Looking at the Endura and RJ ricassos, they look to be almost exactly the same length, I'd say the RJ is less than 1/16th of an inch shorter.
Bottom line, just close the RJ the same as you would any other back lock without moving your fingers any further back than you would any other back lock and you'll be A-O-K.