Heavy’s left testicle seems to be about the same size as one finger, and as wide as two fingers.

The average hand length of an adult male is 7.6 inches. Considering in this game fingers are almost the same sizes as the palm itself, we can assume they’re half that size- 3.8 inches or so.

The width of his fingers are about 1/3 the size of the finger’s height, aka 1.26 repeating percent. Again, the balls are as wide as 2 fingers, so 2.58 inches wide.

This means that this dude (at least, his FNF form)’s balls alone are comparable to the size of baseballs. Guess he’s called Heavy for a reason.