Thank you Kid for your reply. Of the three basic open tunings that you can reach easily from standard tuning, Vestapol - 151351 / Spanish -515135 / Open C - 151513, the last one is the least popularized. Although, with the same interval arrangement you prefer on the 4 highest strings. 15(1513). As you may know, I am very fond of the 513 tuning for 3 string. As far as movable chords go, everything falls neatly in place. extending into 4 string like you did, makes perfect sense to me. Enjoy.
Yes, if you use an open tuning with a minor third, it is easy to fret that note to return to a major third. This is what the old Blues masters called "Cross note tuning". Instead of Open D (DADf#ad), they tuned Open D minor (DADfad). This gives you the same advantage as standard tuning, when playing for example an E chord. The open third string is the minor third - G, playing the chord adds the major third - G#. By playing between them, you create that typical minor / major tension found in the Blues.
As for three string CBG, I found a 513 works out really well for movable chords. This is the subject of my instructional video #6.
A 153 tuning is actually quite unique in regards to the usual open tuning tone arrangements.
Thanks for sharing some more of the endless possibilities. Enjoy your practice, Keni Lee
Jef, just about got your goodie box ready to send off. Sorry no neck in return, but a box full of some of my creations and some wood pieces. I`m sure you`ll like whats in the box !!! I`ll let you know when i`m going to send it off and whento expect it...thx again