I don't know - I've had some lethal ciders in my time - diluted or not...
Mutton fed? (Rough, scrumpie, Pratchett's Scrumble, etc?)
I have had some very good ciders, a friend of mine smuggled some British ciders in, a few bottles each of Stoneham's (Stun'em's) and Dead Dog Cider (complete with the song about how the cider got its name... which did indeed involve a dead dog - rven the name of the dog is remembered!).
A rough cider is quite a bit stronger than one which does not include meat - traditionally a leg of mutton is tossed into the barrel before closing. When the cider has aged there is nothing left but clean white bone.
I have some friends in the SCA who make their own. It is a good deal stronger than American beer. (One has a song about 'Jack palsy, the shakes that result from some of the stronger ciders.
But for a cider shandy I typically use commercially available hard cider and ginger beer. No sense in wasting the good stuff.
The Auld Grump