Hi Rob,
You have quite a large flash memory in genos which will allow you to load in many packs. If you have various voices in UVN format on USB sticks you can go into the YEM and select create own pack and you can load these into this pack. You do not have to load all the voices in a pack into your keyboard. You can remove the ticks against the ones you don't want. As I have now got all the sounds I am ever likely to use I have made up a master install pack on my USB stick which is also my backup should I try anything else. If I don't like what I try then it is easy to load back in my master copy. The YEM is very versatile and I am sure you will get what you want from it.