x5s

Does anyone know any specifics on ND Filters (size, thread type etc) for the X5S or X4S? Since we're waiting on our shipments, I thought I would pick up some filters.

At £1000 for the CinemaDNG license and £550 for the Apple ProRes license (if purchased separately) what are the key difference between the two options and would CinemaDNG really be worth the extra? Would I really need both, or indeed either of the licenses? Whilst I would like to get the best...

Has anyone seen if the X5s will be backward compatible with the Inspire 1 V2? I haven't found any info on this yet.