When I tell him to go through the center, he starts out straight and does fine until we pass the half way point, then he starts drifting. I don't think he has a good attention span at all.
I don't think I'm crooked...I mean I guess it's possible, but to my knowledge I'm not crooked or asking him to move over.
I do lots of circles and figure 8s, and I try not to always work on the rail...I tend to ask him to walk, trot, canter at least 3 feet away from the rail so he doesn't get used to always being on the rail.
Could it at all be an insecurity problem at all? I mean the arena is twice the size of the last one...if not more. It's out in the open where as the last one was enclosed. Just a thought
EDIT: When I go next time I'll try not using the bridle and just use my legs and see how that works. If that doesn't work...I'll take two carrot sticks in both hands and kinda just keep them out infront of him so he's kinda "blocked" into a line...maybe that will work also