1. I watched the how not to gybe an FJ video....it looks like they flipped because they put weight on the tank in order to flatten. Do you want to put less weight on the tanks both when rolling and flattening, or just flattening. Today when the wind picked up I felt like I wasn't rolling enough at all and I was just pressing on each tank.
An FJ is really tippy and doesn't need a lot of roll in the gybes - particularly when it gets windy! Most boats go over because the skipper and crew over-flatten. Your description of pressing is a good one. In breeze, you are just trying to keep the boat stable. The rudder on an FJ is tiny, so the skipper needs the crew in order to steer through the gybe. However, unless it is light, you don't have to really whale on the tanks.
2. Is there a specific way to organize the jib sheets while you're fully hiked and sailing upwind - I try to pull the windward sheet taught so its ready when I tack, but it also sometimes gets tangled and hard to get a hold of.
Yes! As soon as you are hiked, pull the slack out of the windward sheet and drape the sheet over your back leg. This way, when you go to tack, it's right there and you can get your hand on the sheet, by the ratchet, as you go to roll & cross.
3. How should you be set in the boat before a start?
Pre-Start is pretty much the same, just keep trimming that jib! If it is totally nuking, you may even cleat the board up half-way before the start to stay more in control.
4. I know when going upwind you play the jib with the skipper, so when they let out you let out, etc. but how should I be playing the jib downwind while on a reach?
Trimming the jib is pretty much the same. Just watch your tell-tales. The thing with an FJ jib is that it is MUCH bigger than a 420 jib. If it is light enough to trim outside the shrouds, then you really need to make sure that you pull down to keep the top of the sail trimmed, but also ease enough for the bottom to be powered up. As it gets windier, you'll trim through the block and just do your best with shape. If it's a really long down-wind leg - and you don't forget for the upwind - you can move your cars to get a better shape. However, the trade-off is minimal if you forget to reset them for the upwind.
5. Should I be "popping" the jib over in front of the block while gybing like in a 420? I know I probably won't be able to in tomorrow's breeze anyway, but what about when its lighter?
If it is light enough, then yes. An important thing about wing-on-wing gybes in big breeze: you want to pop it through the block and not bring your weight to windward to hand it to the skipper. Just pull up hard through the block so that it is slightly over-trimmed for a second and the skipper can then reach forward to take the sheet. However, it it is psycho nuking, then you actually trim the jib on the wing by pulling through the block from the leeward side. This lets the skipper sit in a bit and just trim the main (one pump on the main could be the difference between upright and up-side-down!)