I ride him with very light but firm contact- he's very responsive and seeks the contact, but he's not really 'on the bit' yet, his training has not progressed that far.
I may have understressed the fact that this horse is very Green. He knows how to walk, trot, halt, back up, half halt, turn left, and turn right. We are introducing the leg yield, but only slowly and after he has produced consistent work doing the former things mentioned. In doing this, I usually put leg on him and tell him to turn at the same time, so he moves around the leg (at a slow walk or almost stand-still). He's doing pretty good, and will move away if I ask directly and very obviously. Spurs are out of the question right now- he doesn't have any problem moving. He just doesn't know what to do.
I don't have an arena to work on a rail. I usually work in an open field or on the road, so we don't actually do a ton of turning or circling like you see in arena work. The problem I mentioned is that when we do circle, his right is fine- perfect. But the left is terrible. Should I avoid doing any circle work at all until he can leg yield consistently? And this is only at the trot. He walks the left circle fine as well.