i have been experimenting with,ef#bf#bd#.[although Ithink of it as fgcgce],you have an open drone for your subdominant 6 string 5,4,strings foryour tonic,5 string for your dominant.
it seems quite easy tp pick out tunes,its based round b major,and quite easy to transpose from dadgad tab,and sounds very appalachian dulcimer like.of course if you bar your top five strings you have different major chords.
another useful tuning that NicJones used to use,is cgcgcd.