I know one of the Henry amps I had used a "camshaft" to engage a array of doorknob caps for the plate tuning side of a pi tank. I'm working on a linear build that I'm trying to find an affordable means to build the sizeable pi tank needed. I've got a 15kv 800pf variable vacuum cap. But I'm still needing to sort how to work out C1 and C2 for this setup. From what I've gathered, I need up to about 400pf of capacitance n C1. And up to 1800pf or so on C2. It wouldn't be hard to find a 500pf variable in 15kv range for C1. But finding the 1800pf variable for C2 seems spendy since I'm only finding new. Could I possibly use a fixed 1000pf vacuum cap that I switch into the network via a cam/conductor or vacuum relay?