I usually just remove my spare at the track and leave it in the garages. They have two rows of carport like things so there is an undercover parking spot for everyone. I suggest all the skylines stick together in the second row back from the track.
There's not much weight in the rear seat so I wouldn't bother with removing that but I do remove the carpet, spare, jack, sub, etc from the boot.
As the for the layout of the day, we will have the proper forms soon but basically you have scruitineering of the cars from about 7:30 to 8am so don't be late. Then drivers briefing. Then newbies go out in the experienced peoples cars for a few laps limited to 100km/h. Then the newbies go in their own cars with an experienced person in the passenger seat for a few laps. Then the day proper starts with probably 3-4 groups each going out for 15 minutes of track time, then coming in and the next group going out.
I don't know why you would want 5 spare tyres Ando!