I can't speak for the Rubys. I'm currently using JJ E34L (not to be confused with JJ EL34, they are not the same tube) in my Quicksilver Silver Sixties with the Gallo 3.1's and they sound excellent. Quicksilver recommends the JJ E34L as a replacement in the Silver Sixties. They sounded good right out of the box. If you don't hear a marked improvement after 40-50 hours I would try something else or you can give Mike Sanders a call at Quicksilver. He has always been very helpful.
Ruby el34s sound flat?
I just put a new quad of Ruby EL34s in my Quicksilver Mid Monos. The highs are limited, the sound stage is smaller and it just sounds veiled. Is this just a bad choice for this amp or do they just need to "break in"? Previously I had Teslas. I am using Gallo 3.1's