One last word of advice (20+ years experience here too), take your seatbelt, put the ltach close to the receiver then twist the latch (& belt) around once or twice. Then lock it into the reciever. The idea is to get it tight to hold you in your seat well.
It's better to focus your attention to what the car is doing then trying to adjust for where your but is going in the seat. Honsetly a good set of 5 point belts is one of the best investments you can make if you plan to do auto-x even semi-seriously.