Part of Yates arm size deficiency is tri size. Great cuts, not great size except in side-tri shots where he's pressing his arm against his side to create an illusion. Side-tri shots are the great equalizer for those without size.
For anyone paying attention, both Levrone's tris AND bis are bigger than Yates', & closer if not quite as big as Coleman's. The size advantage is not just one muscle or the other.