Bryn,
I have just been experimenting with your tuning .I have just been picking out the melody of Adieu sweet lovely nancy,which is in a major key and it works very well,quite a dulcimer type sound.
I used the same intervals for the top 5 strings,but kept my top e and b the same so e b f# b f# but tuned my 6 string to E,Thus I only have to re tune my 3 4 5 strings,of course the 6 string might be better for searching lambs as you suggested tuned down a semitone.it looks like it might be a versatile tuning. B Major is one of my natural singing keys,so keeping 1 string tuned to E,makes sense foer me so thanks,nice one.
so my variation is a sus 4 tuning.Dick Miles