I personally don't like comparisons because they are never really spot on. In other words you might say he is compared to one guy, but that might be just cause he is the only one close enough to the likeness of the player. If you really want someone though that shows similarity to Billingsley, the closest I can think of is Bonderman. As far as body, stuff, & make up goes they are pretty close.
He has the potential to be a #1/#2, but it's always hard to say if someone will ever reach that. In any case though he should develope into a top of the rotation guy if things go well.