Some random comments back at you! 🙂
NB. you only insert on jack at a time: either a mono into the "Normal" socket or a stereo/TRS into the Rick-O-Sound one.
FYI, the switching socket is a Switchcraft part too (I thought I had a note of the p/n somewhere).
I think there may be a sweet spot to allow the mono one free movement.
Perhaps bending the mono one's inner blade in a bit might give it that extra clearance.
The reason there's no sound when a mono jack one is pushed all the way into the stereo socket is because the mono socket's switch connects the stereo one's Tip and Ring together, so if you push a mono jack in all the way, it's Sleeve (Gnd) is touching the Ring, which connects it to Gnd too.