Some people don't want the extra weight of 3/8" ss pins. Nor the weight of 3/16" plate aluminum, which is why Harken, Ronstan, and many other manufacturers are running successful businesses.
I've never held one of your home made blocks, but comparing Garhauer to Harken, the cheaper heavier Garhauer blocks are overbuilt and underengineered. Making them heavier than necessary. There's a reason so many people use fancy pulleys. And it's not b/c they're all too stupid to know better.
On that note, I'll go back to pounding sand...
1/8th inch plate would work for a boat that size, as would 1/4 inch pins. For a boat that size, 12 guage or even 14 guage would work.The difference between that and the weight of the coins in your pocket would be negligible. You could save far more weight by skipping breakfast and sailing bare assed.
Yes, there is a reason people use fancy pulleys. Promotion, advertising , glossy brochures, and hype.
A rich freind sailed from BC to New Zealand and back. He had expensive, comercially made blocks, with aluminium cheeks, with stainless straps over them . The corrosion betwen the two froze the expensive , "comercially made "blocks up solid in less than a year . All aluminium blocks ( the $2 kind ) are open, and any corrosion falls out.
Without the stainless straps to react with, there is little corrosion. Mine are 29 years old, and after 6 Pacific Crossings, and 11 months a year cruising, are as good and functional as the day I made them( for under $2 each).
In racing circles "Overbuilt" means something which doesnt break regularly, reducing profits for those who make and promote them.