My first 320 residential install

[letgomywago]

Look at the drawing, you could have as much as 200 amps on the #6. Imagine the neutral on the right disconnect is broken, now all the neutral current from that disconnect is on the #6 to the left hand disconnect. I would much rather have 200 amps flowing in a metallic nipple than a # 6

Number 6 bare won't have issues there's no insulation. The issue is after this theoretical catastrophe you'll have a welded metallic nipple. Next issue is how likely will this happen a lightning strike could hit a overhead bare neutral wire more often than cutting a neutral in a tap live. This kind of ground loop is on the bottom of issues that could present themselves far from a parallel path of lv wire to a detached building.