Holding the guitar differently may help. See the thread, "Resting the Guitar On My Leg", http://www.guitartricks.com/forum/showthread.php?t=38612&page=1&pp=7&highlight=classical+position .
I have what I consider to be a large dreadnaught and early into my start with GT lessons I switched to holding it in a way similar to classical guitar players. I thought it was more comfortable and I know I gained better/improved reach with the guitar in that position.
I sit when I practice and should I play standing up I find the guitar is in nearly the same position as when I practice. That can be a pretty big benefit too.
"It takes a lot of devotion and work, or maybe I should say play, because if you love it, that's what it amounts to. I haven't found any shortcuts, and I've been looking for a long time."
-- Chet Atkins
-- Chet Atkins