This^
I've shipped thousands of pedals this way. Never lost one or felt I overpaid. The box is free and sent for free to your house in bundles of 25.
https://store.usps.com/store/product/priority-mail-medium-cube-shaped-box-P_O_BOX4
Uline is one of the worst american companies of all time. And they bankroll the very worst of american politics. I wouldn't shit in one of their boxes unless i was mailing it back to them.
Or, you could avoid the shame of white washers and lock washers and upgrade to a decent footswitch with metal washers and spring washers.
https://www.taydaelectronics.com/electromechanical/switches-key-pad/stomp-switch/alpha-3pdt-stomp-foot-pedal-switch.html
The lack of rate LED is concerning. The trimpot has to be biased to get effect but the rate LED should be going regardless. Is the blend pot insulated from shorting out the back of the pcb?
https://www.pedalpcb.com/product-category/components/optical/
He sells photoresistors here. You'll have to compare specs to the KE-10720.
The MPSA18 is super common. Every parts supplier should carry those.
They were the standard when I first started building in the 90s. Great for noobs because you can't accidentally melt them like box caps. I'm still nostalgic for them and use them in my personal and legacy builds. I don't know of anything new that have their form factor.
Super cool! I used to sell this exact configuration, and a sm/vfm with the same features (switchable big muff tone stack with post boost) and a voltage starve.