re: Pinching Rod

They're great little aids... and I commend you in the degree of supplied parts MrR... When I was introduced to them, I never considered making my own from scratch and the availability of those brass knobs... Aussie supplies were (and still are) limited.
Many years ago (15+) when I still lived in the big smoke, one of our stores had a swag of Veritas hardware to make them marked way down in their reduced clearance bin and I bought out the entire bin's contents (around 1 doz.), to hand out to buddies... I was more amicable back then...   

I retained 4 of them with the last small set made not that long ago for small projects,

For anyone contemplation making a/some set(s), may I suggest, for outside measuements,

some small dowels into the tips to remove any need to make "hook tips",

(my hardware came with brass pins).