Nice writeup. Lead does not produce fumes or vapors below 1200 degrees F. So any fumes produced come from impurities burning off.
If you have good pure lead, I found no need for respirator or even a fan in a large enough area (concrete floor or workbench in garage would be good) Lead poisoning more likely to occur thru handling lead and ingesting it. Gloves, goggles and clothing to cover all body parts are essential but no special clothing needed. Finding good source of lead seems to be biggest problem.