I went from an open E tuning, half a step at a time, down to open Bb before I realized that I could just tune up to open G. The string guages that I had to customize were costing me a fortune when trying to tune lower. The looks I would get from music stores when I'd inquire about the guages I needed coupled with their lack of interest in acquiring and stocking what I needed was driving me nuts. I had to run all over town just to buy a change of strings, checking for the availability of a heavy guage set at one of several locations and the custom low E string from a specialty bass shop miles away.

I may eventually customize a guitar to suit my needs for really weird tunings but for now I've managed with one guitar tuned two half steps low of standard, because it fits my voice, and my homemade Nobro (my Dobro/National hybrid) in and open E form but scooted up three frets to make it open G. I have another guitar tuned in open E and a fourth in the same form but down two frets to make it an open D and my plectrum banjo similarly tuned but in open C. There are enough git boxes around to mess with all kinds of tunings. I've only scratched the surface.

Keep scratchin'