SunRazer
Back From The Dead
Well, they were certainly around by Fae's time. So the quote suggests that Fae had the best record with the Muntuur Stones from the end of the New Sith Wars (when she became Grand Master) up until the writing of The Jedi Path, which was published in its third edition in 115 BBY (which is the one that we're looking at).
Couldn't find the section on the Muntuur Stones in Nexus of Power in my brief skim through it, but it's safe to say that as of the writing of The Jedi Path, Fae's lifting of six Stones was considered unprecedented, with Yoda lifting six also before reaching the age of 700. Ferleen Snee was reputed to be the only one who lifted all seven, but again, there was no date available for that.
The only question is how long the Stones have been used as practice by the Jedi, as you said. Unfortunately I can't answer that as of now. If someone manages to find the part with the Muntuur Stones in Nexus of Power, they might be able to tell you.
But as you said, the fact that Yoda was impressed by her feat of telekinesis is no small accolade in of itself.