combining several regions on sd card

hi, i have a nüvi 1450 and would like to add europe and australia in addition to north america

the gps reads my 32gb sd card with no problems

i've downloaded and combined gmapsupp.img of north america, europe and australia using gmaptool

my question is, what do i do with the gmap3d.img and .jcv files from the 3 regions?

do i need to combine gmap3d files to make sure i get 3d on all continents?
the jcv have different file names. do they all show correctly during navigation if copied into the /garmin folder in sd card separately?

there's also a bunch of .sid, .g2s and .db files from different regions. do they have any function or necessity?


thanks for the help!