"Regarding the 3 position switch. The simple solution is to put a
capacitor between ground and the output side of the switch. The
capacitor must be large enought to provide the current needed during
the switch switching time. This should not be a very large capacitor
for our purposes."

This brings up another issue. Switches may be rated for ac or dc (or both).
Many of the switches sold at the local electronics supply house are not
rated for dc. And, some may be less reliable than others. Many are not
rated for the current you want to run through them. That means likely a
failure. It could also be worse, with a possible fire.

When you get to rotary switches, contacts may be configured to make before
break, which means the rotor will contact the new contacts before
disconnecting from the old. This is another subject.

Colin