[Repair/Restoration] Diecast replacement parts and spring size for shoulder ratchet?

I recently got this guy off of eBay for really cheap (*for obvious reasons that don't involve getting a Prime killed*), and I know this version has a lot of fragile parts. I know there's replacement parts from ABS you can get from china, but they don't seem to come with a spring and I've heard that they don't fit as well as the original pieces do. Plus, I honestly think using a diecast/alloy piece might be better for long-term durability.

Before I start making my own parts, I was curious if any already exist? I know there's a lot of replacements for the knees (*that do come with springs*) but the only thing wrong with this guy is his shoulder joint, and the fact that his spring for that arm is missing.

Speaking of springs, does anyone know what size springs are used for his shoulder ratchets?