hi.. i've got a 34" scale 6 string bass/baritone guitar:

slightly less than 2" fingerbord at the nut;
2+1/2" at the 12th fret;
2+3/4" at the 24th fret..

and an almost flat fingerbord radius...

using very light gauge bass strings....

i'm currently bodging it with an old standard 6 string electric Dunlop capo
that just about works ok without too much fret buzz
but its obviously too small and fiddly to get it in position quick enough...

so any suggestions please,
for a good apropriately wider quick release capo
[probably for 12 string acoustics???]
would be well apreciated..

thanks.....