Iv made one of these at home making the drippers was the hard part. My shot turn out a little sad haha, i get little footballs or dish shapes, very few are round, and the shot group opens up rather fast. But i like the first video the fellow is using a rag as the drip lip. I will have to try that at home, i think that maybe the trick. With a damp fine weave fabric it may roll and cool at the same time instead of deforming in the cooling bath. And possible an extra long drip lip may allow extra cooling. I have couple pounds of drop tower shot made in the 60s some time that was given to me and it has 10% with tails, while this stuff looks nicer.
I made my drippers out of 3/8 brass bolts, kinda pricey $12 a bolt, and drilled through the tail of the bolt and used a pin drive to intersect the hole from one of the 6 side faces of the bolt. They work great only issue i had was the drip will slow if left unattended, but once the pot is tapped a couple times with a spoon she starts dripping like crazy again.