FWIW, I've used needle threaders for decades, and I've only experienced breakage of one or two small blocks in all that time. I even purchased a set or rigging tools... which were basically 30cm (one foot) long wooden dowels with various metal tips glued into the ends of them. Many were darning needles that had the eyes cut or reshaped under heat to provide a variety of hooking and grabbing tips... but one of them was basically the thin wire from a needle threader epoxied into a hole drilled into the end of a dowel. I use the clamping hemostats as well, but for a slightly different purpose. I may use them to lightly hold a block steady as I'm running a line through it, but what I use them for quite frequently is to provide a weight to the end of a line that's been run through a block to keep light tension on it while I'm getting ready to run the end of that line through another block or fitting.
I really like the looks of what you've completed so far... really nice, so suffice it to say, "keep up the good work!".
