world comp, with weight maps

building world from world machine, setting up tiles for export.
Now I wonder for performance in UE4, is it better to tile in smaller chunks like 2017, or larger chunks of 4033-8129rez. to help understand my project, there will be water features, ocean, and river, small lake; foliage, and cliffs the size of the landscape is 14kmX14km.
this project is not for actual game, more for making a movie/series of short films, so final product would be rendered as movie.
so my question is for working/development would it be wiser to use smaller tiles in my world comp? for performance concerns.
my system specs, amd 6300, 7700 amd gpu 1gig, and 16gigs system ram.