The key with building big jumps is to build safe ones. The bulk of your business does not come from A-Riders. So big jumps with forgiving landings is the best way to go. Single to table top as listed above, Big table tops, Step-ups, larger doubles with big round landings, triple with rounded landings. Basically you want stuff that a C-Rider can try and not get hurt if they mess it up, You want those guys to have stuff that allows them to feel like heros in front of their friends and family. If you have the space you can put in a split section one where A riders or A/B riders go one way and C riders go another. I love the 4 race spread out format and I definitely think two motos of about 4 laps is the way to go. The times listed above are golden too 4 practice 6 race. WRMC used to have a series like this and it was my favorite ever.