Ibow: I missed the reference to the Bear weather rest. That should have straightened the arrows out if they were close to begin with.
Are you saying the 2016s seem to be shooting clean and impacting where you want them to, or are they still going high and right? At 60# static spine, the 2016s should be heavy enough for your set up.
I have several 64-inch ACSs from 50# through 56# at my 28-inch draw. Easton Axis .400s (about 80# spine) shoot well out of all of them with 250 up front. Gold Tip 35-55s (about 60# static spine) shoot well out of my 50# bow, but are too light for 52# and up at my draw length.
Ron W raises a good point. The standard grip on an ACS is very close to a medium recurve grip. It is a rather small grip, though, and you could be torquing the bow as you grip and/or draw it.
Also, the arrow may just align differently vis-a-vis your eye with the ACS vs your Widow. I.e., you may be holding your bow hand in the same place, but that hold may move the ACS riser/arrow more to the right, and even higher, than the Widow with the same grip/hold. That little difference is one that a lot of folks find hard to get used to as they switch from one bow to another, particularly recurve to longbow or vice-versa. Your brain is placing your bow hand in the right place, at least where it's always placed it, but that is no longer the right place for the way the second bow is cut.
Try this, next time you draw on the target, look down the arrow and see where it's pointing. There's a good chance you're unknowingly pointing it right and probably high of the target.
Of course, there could also be something in your style that's throwing off the arrows. For me, a right high hit is usually associated with a pluck. When I pluck, I seem to also push the bow a little at release. Keep at it. It will come around. Good luck.
Of course, if your 2016s are not only flying straight, but also hitting where you're aiming, you've already solved the problem.