After digging around, I've found out about spring balancers. They sound like the thing I've been looking for (see previous log) in that they're a tether used to counterbalance tools to prevent strain on workers. The cool feature is that the balance force is adjustable, which is even better than a constant force or gas spring strategy. It also requires much less effort on my part to implement.

• YH-602A
  • https://www.aliexpress.com/item/1005003788306775.html
  • The cheapest I found, coming in at £68 total for 8 (4 per SecSavr) delivered and with UK VAT added.
  • Might be unsuitable since I can't find the length of the cord, and it's smaller than the other two, implying that the cord is shorter.
• SB3000
  • https://www.aliexpress.com/item/32814716324.html
  • £91
  • 1.4m cord
• SC128-ES630
  • https://www.aliexpress.com/item/1005003990815337.html
  • £71
  • 1.5m cord
  • This is the one I'm likely going to go with.

I'm thinking that it might be possible to connect the cord ends together for SecSavr installations that have a Z height that exceeds the cord length of a single spring balance.