Hi fellow Rancilio-ite.
We seem to be in about the same place. My Silvia has rust in the chassis and so I completely disassembled it yesterday. Got that far, decided may as well take the boiler apart. Was surprised how little scale there was for what is a well used second hand machine. I was reluctant to immerse the electrics, so turned the top upside down and balanced it then filled it up with descaling solution. The rested the brew head in a bowl, keeping the (OPV??) out of the water.
I took photos and notes along the way, but only hope I get it all back together again!!
Good luck with your reno.