It's why I just said care is needed. There are exceptions to all the rules. If you're writing classical CPP stuff, it may be best to write the strings in 4 part harmony like "the greats" did, with the DB double the cellos at the octave down - sometimes exactly, sometimes pizz or rhythmically broken up but still following the cello part. As things developed the DB has been given greater independence. As you spotted it all depends on chord layout too. There are times when you want a dense thick sound in the bass and the process is as applicable to brass and w/w as strings. E.g unless it's a featured solo, composers rarely give the double bassoon an independent part but if you wanted a grumbly, threatening effect, primeval things creeping up out of the swamp! that might just be the thing to do.
Ordinarily, if you want clear sounding chords and harmony you put the big gaps at the bottom and follow rules like don't double the 3rd if you can help it (except Va to VIa) (aside from the doubling of cellos and basses. After all, that's a reinforcement issue rather than timbral.)
Anyway I've already commented on this person's efforts several times with no acknowledgement or thanks when I really should be putting time in on a project even if stalled by this latest virus thing) so I won't be commenting again. This composer has all the hallmarks of someone trying to orchestrate with almost no study of orchestral writing. Rather than churning out more stuff her/his time would be better spent studying a Beethoven Symphony score. I'd recommend his 3rd or 4th Symphony - the latter, peculiar for several reasons.