How do you stop pops in rotary switch when selecting capacitors?

[PRR]

> would the use of a shorting switch eliminate

No. It will POP when the two caps equalize *instantly* as the contact hits. The large resistor equalizes slow (sub-sonic).

If at least one contact is always in use, I'm not sure what Merlin's red-mod adds. If the switch will go to a Not-Connected position, his mod is one way to deal with it.