Doesn’t really matter, there’s a cafe called the shed doing really good burgers just up the trail from the black/blue/green car park though (Brechfa?), so worth planning arroud that for a lunch stop, but I can’t rememeber where on the trail the link between red and black is if you do them as a loop, so best to start in a way that drops you at the cafe halfway round.
To do the Shed for a lunch break (open Sat, Sun and bank holidays), start at Abergorlech. Do the red then before the final red descent back into Abergorlech turn right to pick up the black. After the 2nd log bridge on the black (with the log balance lead-in) the trail brings you up to a lane. Turn left here, rather than right, and follow the road down for about 200 metres and the Shed is on your left.
After your burger or whatever, retrace your tracks and continue up the track to the fire road. You can then turn left to do the final bit of the black down to the car park (or the green, which is even better IMO) or turn right then left to start the big climb on the black and work off your lunch. Follow the black round and it will deposit you just by the start of the final red descent again.
The blue/green is more climbing than the black
No way. Much more climbing on the black.