Oh, no. You have to go orc because being an orc is the only way to get to ~150 *base* attack. Because you are an orc and a transmuter your attack *percent* is in the toilet. So it's best to use items that focus on attack percentage because "orc transmuter" largely takes care of the base attack.
Stacking attack % is nice but the stacking bonus puts orc way way over humans with the transmuter. That makes me think, the only other stacking racial is Goblin. I wonder how that'd go.