I think if we were going to add -30 records into the Book of Records, it would just be a mirror of what is currently in the Book of Records, but with -30 gravity.
I personally don't like the idea of tricking being part of the Book of Records because of the large spectrum of tricks, a possible lack of accessibility to those who don't really know what some of the tricks are, and difficulty in defining some of the records. I had no idea what a dub cork is, or what a stall into a gyro is until now. And looking at how you described the latter trick, I think it's too complex, and not easily measurable (I could be wrong. maybe Glimpsed can give some feedback on this since he's 1. A BoR keeper, and 2. experienced in tricking) All the records in the BoR have simple goals that anyone can understand. I feel like having tricking records might not be very accessible to everyone, and because of the large variation of tricks, could absolutely flood the Book of Records with a bunch of records for every single trick in the entire tricktionary. Running records were removed because they became a giant grey area of what is actually considered a 'run', and it's entirely possible that adding tricking records would see the exact same thing.
This can be a topic of discussion amongst the BoR keepers, but in my opinion, I think only -30 varations of current records would make it through, if it were to be implemented.
We can't forget that record bounties are a thing and with the amount of TC being given out because of all the new records (basically considering every record in the BoR as a new record), could inflate the TC market. This would need to be discussed with those who payout the bounties.