My first kit project was from SWTP too, and the follow up to their Therimin.
Thought I was a pretty good solder slinger until I tried to build the SWTP Kit. So many DPDT switches.... so many white wires...... so many off value resistors.
Sorry, can't remember their kit name (their version of a Moog Sonic 6, simplified)only worked in private, was never able to show it running to a living soul.
My best friend built the their therimin, he was one of the folks that wrote to Don Lancaster at Popular Electronics seeking assistance.
All in all it was big fun.... and we're both still slinging solder well on 30 years later!
Cyclotronguy