Try loosening the rail screws where you have play and taking a scope ring and bridging the receiver and forend rails. Tighten and you should align them, then tighten your screws a little at a time evenly on each side. Then remove the ring and see where you stand, this may solve your issue and may not. However, I've found this is the easiest way to mount the Troy and Samson rails straight, hope it works for you.
J