Out of curiosity I checked what breakpoints the 13 bane damage hits. You'll one-shot marines assuming you get +1 before they get combat shields which seems reasonable. You could go down to 12 if you get +2 weapons before the enemy gets +2 armor. Something to note is that Zagara's baneling spell benefits from the mastery but not upgrades so it will barely miss the one-shot, but with 6 banelings and zagaras splash attack that is likely not an issue. You could also invest 18 points to one-shot medics with +1 weapons or 22 to one-shot them without upgrades. No other units in classic infantry have breakpoints higher than 12.
