Royak,
I'll pretend I'm Greg........LOL

How much weight do you need to knock off that thing? The reason that I ask is that the Guardian has super long limb bolts which allow it to be turned down to the point where you can actually relax the strings for work without a bowpress.
Even if you need something like 56-57# or so on those 70# limbs that really shouldn't be a problem. If you look at the holes in the riser where you can see the limb bolt threaded thru, just make sure you don't back them out to a point where they start to leave that upper smaller hole (thread bolt sight port)

Turn it back to 60 and see how she feels, You won't change the efficiency enough to warrant a new set of limbs if you can handle the 60#.