Done them both many many times over the years. The slab has actually gotten worse over the years. Back when they first ‘uncovered’ it the granite was so fresh you could do a track stand half way down the grip was so good. Now it it coated in a layer of rubber and much slippier imo.
Its still one where its more a case of relaxing and letting the bike cope with it than skill. Think about it, the ‘ruts’ arent much bigger than a tram line in a town centre. You would trust your 5yr old to ride over them on the flat.
The qualifier is harder for me but again, as long as you have the bike under control and dont let it gather too much speed (Your back wheel starts to skim the rocks) its again a lot more down to relaxing than skill.
I did them a few years ago on a night ride which was fun. It took a couple of goes but managed to get the qualifier and the slab without stopping which added to the excitement. As you approach the slab your lights are pointing in the air then BAM, you are pointing down the slab with no chance of picking a line. Great fun.
I am officialy a pussy now so i can say this without being a big head know it all 🙂