I guess a good place to begin might be just using 1st violins, 2nd violins, violas and cellos (forget divisi writing for now) and have them sustaining the chords not greater than 2 octaves apart. Use a specific patch for each one so they can be panned properly and it’ll give a much better sound in the stereo field from left to right than a pad. Though you can write the harmony as a pad first and then split the 3-4 notes up, obviously lowest note to cello and highest to 1st violin. It’s all good practice anyway, and strings do work really nicely for piano ballad kinda stuff. I really love the string writing for Vanessa Carlton’s first albums.