"I only have seen it a handful of times in Jedi texts. Which is unsurprising - it wouldn't normally develop in the Jedi. Part of ones' Knighthood Ceremony is cutting all bonds with others, which would nip such a bond quickly." Well. It was what one was supposed to do, but it had been an open secret that Anakin Skywalker and Obi-Wan maintained their training bond long after Anakin was knighted.

"What the limits are partly depend on the individuals bond. Obviously the more trained and more powerful the pair, the more powerful feats possible. If theory it could create a pair who are singular beings. Two who are powerful enough to act as one, even over vast differences." The academic conversion was easy. Easier than the previous one.