Just something I noticed when working with the exporter: It seems to
export a material information for every single group, so if you have
several groups with the same material, you should select them all and
join them by hitting the "regroup"-Button in the "Groups"-tab.
Depending on the mesh this can greatly reduce the filesize - one
example i came across was a ventilator which had 37 kb before and 25
kb after joining.
Of course filesize is not a problem these days - but i guess it will
also take up less performance in-game...hope you'll find this usefull.