At the moment, GT black is mostly useful as a way to access the offpistes.
The red is mostly unaffected by diversions EXCEPT for the absolutely bloody stupid signposted diversion up pennel’s vennel, which just makes no sense, it’s a horrible pushup for one short descent. Instead just ignore it and carry on past it, it takes you into the red climb anyway for the loss of just one trail. Or, if it’s quiet, just push up beside berm baby berm, it’s an easier push and not usually proplematic.
(is falla brae still shut? I’ve heard conflicting versions of this… Was diverted down the blue last time I went to ride it)
The new stuff is really easily accessed though the signage imo is a wee bit unclear. You can loop it, session it, allsorts. The loops at the bottom and the new blue are imo better done than the main new red The Twitcher, which is mostly just very fast with a couple of good jumps- it’s over very fast and loses a ton of height, good but inefficient.
(stw people seem to be down on the new stuff, we fear change,but it’s incredibly obvious just by looking how popular it is, a lot of people’s GT ride is now just laps of it, and there’s swarms of people sessioning the bottoms)
If he’s up for a little bit more the newer offpistes at GT are absolutely superb- well built, and mostly not as mad as tweed valley offpiste tends to be. And easil accessed too. Skullduggery is imo one of the best trails in the valley and it’s only a small step up above the reds.