MicMac & Vic...I made a mistake on my "closed Bb" fingering description....I thumb strings 5 and 6, and use my third [ring] finger on the 2-3-4 strings, not my index.....sorry. :oops:
Dogbite...I sure DO use your "closed C7" position up the neck...yes, particularly for the six-note E7 in fret 5, but frequently in other frets as a four-note chord.
A nice additional feature of the closed C7 is the close proximity of the closed C9 series, which is x 3 2 3 3 3, and can give a jazzy flavor alternating with the dominant 7th...sliding up into those C9 chords gives a T-Bone Walker flavor.
Other "closed" chord shapes I use a lot up the neck, that involve thumb-hooking:
The "closed" Fm : 1 3 3 1 1 1 , with T, 3, 2, I, I, I
The "closed" Bbm : 1 1 3 3 2 1 , with T, T, 4, 3, 2, I
These are much easier from the fourth fret up, than they are down the neck.... :wink:
"A child of five could understand this...send someone to fetch a child of five !"--Groucho Marx
I have exactly the same problem except it's the end knuckle on my left index finger. The knuckle was damaged and it has a bump on the thumb-side. It creates a gap between the two knuckles that makes barre chords difficult - particularly chords where my finger is turned on its side. I have been experimenting with the finger part of a glove that has a leather pad that fits in the groove between the two knuckles. It is flexible enough to bend when not barring and narrow enough to fill the gap. I think a rubber band about 1/2 inch wide would work fine. The glove finger is strange looking and doesn't fit tight enough but it does work!
Cheers,
Doktat