I had a local metal shop build cages for my Quicksilver amps (see my system page). A bit more expensive but not outrageously so. I very much doubt you'll miss anything about SS going to a KT88 based PP or Pentode amp (the silver 90's are Pentode). I've had the 90's and MiniMites as well as two prototype amps Mike Sanders built, one of which I still have and will never part with. I liked the 90's for what they did best (rock and roll and orchestral music.....layered complex music), but for most of what I prefer to listen to I prefer his PP designs. The EL34 is a more delicate sound in comparison to the KT88/90 and there you may notice a bit of low end difference, though I've not perceived it as something I'd yearn for. The V4 are supposed to be excellent amps but I have no experience to convey. Which preamp and speakers are you using and how efficient are the speaker?
Marco
Marco