As the above two posts mentioned, you can put 845 on top of the twins. However, that now means that you are finished with SG for now, since it only plays nice on top of AIO or itself. You can put anything on top of AIO, but once you use SG on top of it, you either can add more layers of SG, or top it off with a wax.
And, as mentioned above, it certainly would be a good winter combo.