In the current public version of the plugin the floating hands were done as a combined mesh and I didn’t clean up the rotations back when these were made (cost of learning as you go). The alpha plugin has this fixed by using separate hand meshes which have their orientations appropriately placed.
Even without the alpha plugin though, you still have options. If you look at the animation blueprint you can change the offsets used for each hand (pre and post base) to match your hand setup. You can also use Animation Retargeting to remap bones https://docs.unrealengine.com/latest/INT/Engine/Animation/RetargetingDifferentSkeletons/ and add offsets there. If both of those options don’t suit, pm me for access to the alpha plugin.