The preamp and amp is an SMc Audio preamp and amp. I am going to have to get the measurements from SMc.
If you don't hear back promptly, just grab a multimeter. Turn the amp on, and check the resistance across signal and ground pin on your input. If running balanced cables, either signal will work to keasure, and you'd need 2 caps per side.
Also the big thing with mixing metals in signal wires is coated or mixed metals will have different conductivity and thus different speed of electrical current. Silver coated copper would have the outer skin conducting slightly better (faster) than the center copper and could create phase issues between high frequency and low. If a section is just silver or just copper then cool, but you also wouldn't want + signal to be silver and - to be copper. Granted this is for ultra super trained ears, but do you want to take that risk? Lol. Silver or copper wiring by themselves is good, just try to find very good dead soft annealed silver which tends to not have that glare and sharpness people have talked about. OK silver wire is meh, good silver wire sounds very good.