It did NOT work for me. I experimented exactly that combo 1 jar + 2 silvers. Ended up giving away the silvers. I knew about this well-known possibility but I had to try it myself to believe it. However, I was able to keep a pair of bala sharks together with my jar for about 13 months with occasional nipping/chasing but the balas are faster than the jar so things have been fine. Well, that was only until about two weeks ago. The smaller 8" bala was suddenly nipped by the jar and that caused it to jump and hit either the glass top or tank wall and died. I did not witness the incident but only heard some noise in the tank and came to check it out and found the bala upside down and dead in less than a minute. It was in excellent health. Now only one 9" bala and two 9" plecos remain in the tank with the jar.
That's my experience.