I actually doubt that any satellite system will ever be attached directly to
the core networks :-)
I am more concerned by the probability of loss in the satellite channel (no
flame from the PHY guys please, I know the link is almost error free but
almost is not fully). Hence the probability that one segment of a packet is
lost is proportional to the number of fragments and then the whole things
may be lost (if no higher layer recovery mechanisms) so much to say for the
savings of encapsulations. I would vote for 16k.