Black is worth the effort if you’ve not done it before, more remote and quieter than Red. I wouldn’t necessarily recommend a rigid HT for the Black (I certainly didn’t think that was "comfortable", quite the opposite probably!) but other than that, the main thing would be to have a bike you’re happy to climb on.
I generally prefer FS on the Black (took my Prophet MX round most of the Black on Friday which was awesome fun on the Boundary Trail and Deliverance) and HT for the Red, but despite the impression you may get from people on here, there’s no byelaws on what bike is permitted on what trail.
It’s all good fun.