That "mutes the acidity" thing reminds me of a guy at a diner who insisted on cold glasses for his orange juice. Said it tasted less bitter that way... I tried it once and honestly, it just tasted like cold orange juice. Maybe some people just feel the temperature more than the actual flavor.

We ran it at 300 for the heavy stuff.

You mentioned the spring could have hit his arm instead of the workbench. Do you know if he was using the proper winding bars, or just trying to make do with whatever tools he had on hand? I've read that using anything but the right steel bars is asking for trouble.