Newbie poster here, so please be kind. 
Started on THE musical path 34 years ago, as a pipe band tenor and bass drummer in high school. College, marriage, and family put participation on hold, but I kept up by listening to Fiona and other NPR programs, as well as LPs and CDs.
Got back into playing about 10 years ago, with a Gen high D. Found it too shrill for slightly-damaged hearing and went to Low D about two years ago. (Avatar boy is playing his current fave Howard; also own a Susato and a Pakistani Low D, as well as a Dixon Low G) Also two years ago, started on bodhran. Now in a five-piece celtic band based in Bucks County, PA.
About two months ago, I bumped into another local pipe band and remade acquaintances with the drum major, a guy I knew “back in the day.” Had an opportunity to march with them at a local Ren Faire (I played bodhran in a tenor-drummish style) and have sat in on a couple of rehearsals.
Long-winded way of now asking: has anyone had experience playing whistle alongside GHB? I’m interested in expanding beyond the mostly-Irish stuff my band does, as well as playing descant or harmonies with the GHB guys. I know volume will be a challenge, as well as the semi-chromatic nature of the GHB chanter. I’m wondering which might work better: a Bflat or Low G, tuned up to A=460 or so.
Suggestions? Rants? Thanks.
Ned O’ the Hill
What you need is a tuneable Eb flute or whistle and a portable amplifier.
Why Eb?
→ Pipers actually play in Bb instead of A. Thus, the corresponding whistle needs to shapen by 1/2 a step to play in tune.
So why not a Bb whistle? → Because the Pipe scale has an extra note (“g”) below the A in their scale. So, you could get a Bb whistle, but you won;t be able to play a lot of the tunes without a lot of adjustments and messing about with octave.
On an Eb whistle, you can get that low 7th audibly; all piping tunes will fall naturally and easily into the whistle range.
You’ll need an amp to be heard over eveything else!
Also - listen to as may Tannahill Weavers recods as possible - Phil Smillie has done duets with pipes for something like 30 years and he’s very good at it.
Thanks for the tips, Wormdiet 
AAMOF, I’ve had three Tannies CDs in the truck’s rotating player for the last two weeks.
My Celtic band is also gigging for the pipe band’s Burns night dinner, so I’m trying to ramp up for possible duets.
I spoke to Colin Melville of the Tannahill Weavers about whistling and Scottish music in this interview. They use both Bb and Eb whistles in concert. Hope it helps!
Use an Eb for the Big ones. It would be better to see if any of the Pipers have Smallpipes or Border Pipes that would make it a lot easier and if they have an A set use a D whistle if it a Bb use an Eb if it is a C set use an F if it is a D set use a G, Scottish Pipes play a mixolydian scale (major scale with a flat seventh) so that is what would work for the non GHB scots Pipes other wise get a Mic and an Eb Whsitle which will need to tune up a bit to be in tune with the Pipes (make sure you get a tunable one).