Success! LDR Resistors do work with SPST switch in series. Only caveat is that it’s need a normally closed switch. The normally open switch does work but guitar is muted and turned on when switch is pressed. Will order some normally closed switches. Unfortunately high quality ones are rare. Either way I’m pretty happy. Found 2 methods that work with an SPST normally closed switch and a SPDT on/on/common switch. I was also lucky to find some 10 spdt switch nos

LDR Resistors do work switch in series. Only caveat is that it’s need a normally close switch. The normally open switch I had does work but the sound is muted and turned on when switch is pressed. Will order some normally closed switches. Unfortunately they are rare. Either way I’m pretty happy. Found 2 methods that work with an SPST normally closed switch and a SPDT on on common switch. I was also lucky to find some 10 spdt switch Switchcraft 963 1A nos on ebay for a steal. If they I’ll buy more. The only spst normally closed look pretty frail.

http://beavisaudio.com/projects/LooperSwitcher/

Edit- looks like I’ve been using a normally closed switch for testing. I ordered some cheap no and nc switch from amazon. Also found some cool steel ones on wish.com https://www.wish.com/product/5f5b504e25ce70190b644640?