Rolling for Damage with the Central Limit Theorem

I've been playing a <em> lot </em> of Baldur's Gate 3 lately. My party has gotten to max level, and we're running around, casting spells and taking names. One of the spells my wizard has is called <em> Disintegrate </em> , which gets summarized like this <i> </i> ImportantDisintegrate Shoot a thin green ray from your finger. If the spell reduces the target to 0 hit points, it disintegrates into a crumbly ash.