I thought about C-clips... with hammer and trigger in, it might be hard to install and deinstall (especially hard to see hammer pin groove due to the wrapping hammer spring).
Waiting pin retaining plate to come. Most reviews say it's good, some reviews complaint plate fitness, too thin etc. I will know very soon
But, don't you agree this being a design fault? The "paper clip" is simple in structure, easy to make, low cost, lots of advantages, but obviously easy to install for dummy was not in the original consideration. For this tiny wire's important function, I would think the retaining plate solution is much more appropriate.