re GHB- playing ch mi na mor bheanna- retuning drones by shutting off th etenors and tuning th ebass up a major second is not such a great idea-   migt as well play it on a shawm. Most pipers are perfectly comfortable with the drones in A against a tune in B minor...BUT you could play it on border pipes in A minor, cross fingering the f natural and c natural and have drones playing the tonic.