uncommon violin family (violin-octet) instruments

Hi.

I am writing a quartet for violin family instruments retuned to approximate some instruments from the "violin-octet" model. (https://en.wikipedia.org/wiki/Violin_octet)

Each instrument from the standard string quartet is being replaced with one instrument lower in pitch. So two violas instead of violins. Instead of the viola, an octave violin (which will be a viola with octave violin strings - so g, d, a, e but all an octave lower than a violin), and the cello will be replaced by a cello with alternate strings tuned a perfect fourth below (so also g, d, a, e, but an octave lower (2 below violin)).

I remember being able to change the tuning of an instrument string by string. Is that just for fretted instruments using tabs? Should I compose it as though I'm using ukulele family instruments so I can tweak the tuning and then put the score back in typical bowed instruments to hear the play back?

Or is there a way to get octave violins that is more elegant that I am too slow to pick up without help?

Thank you.

-Heather

ps I just posted a pic of what the score will look like. I didn't post the score because I haven't written it because... I can't figure out how to choose the appropriate instruments.