That naturally matters. If anyone used it their strength would've been far greater, and her trickle far more if she could've used the sa'angreal without the others. How much did Callandor yield at the Cleansing? It had a ring with men and women, and looked like it pretty much had control. Or when Rand and Nynaeve linked using both Choedan Kal. Did they magnify the circle, or a Forsaken strength woman and the strongest man who ever lived? With Callandor there were constraints because only men can use it and only some were Bonded, but magnifying any amount of Power by a strong sa'angreal must greatly strengthen the ring.

Any of that works for the leader, too. One advantage rings give is many strong angreal with many strong channelers to lead. A leader with an angreal will increase a ring by their increased strength, and perhaps more if the effect of the ring flowing through the leader, or that person weaving it, is increased by the angreal, too. If that's the case there could be an effect similar but possibly less than the angreal on one person that makes the whole ring stronger.

A lot depends on how strong "strong" is. A good angreal will increase strength several times normal, so if a good sa'angreal can manage even ten times that this one could've increased Egwenes trickle fifty times. That impacts the ring for sure, and if it increased it a couple hundred it could be quite impressive. If it increased a large ring even half as much it would be stunning. We'd have to see more rings with sa'angreal, and using those and/or angreal, to have a clear idea.