Hi Cicarda, welcome to the wondeful world of Snobdom, you sound as though you have done heaps of research and are on the right track with most aspects of Silvia. There is a little mod to the Rocky to make it stepless, if you search in the grinder section youll find it, it gives you fine adjustment and only costs a couple of $$, well worth doing.
Maybe do a Gronk and place a thermocouple on your boiler so that you can monitor boiler temp and know when to pull your shot ay the optimum moment!!
Enjoy your espresso journey................cheers gm