Firstly Centre sheeting (Sorry if I'm re-covering somethings but this is how we (AHPC) do it):
We have been putting these onto Aclass, Taipans, Tornadoes F18s and F16s for the better part of, well forever, so we have it down to a fine art.

1/ Connecting to clew of sail; this really isn't an issue as the main sheet is attached in the exact same fashion regardless of the system. That is with a loop of webbing/dyneema through the shackle on the main sheet block around the boom and through the clew of the sail. The outhaul either attaches to the clew or the loop.

2/ Usually you need to go to a larger boom section due the the central loading of the boom.

3/4/ Our tramps are reinforced, you never pull the block out. The tramp will rise up a little but the material (chickpea) has a little stretch and has absolutely no effect on performance.

Using it;
Cleat;
A what?? I have never used a cleat in the main and never will... oh and most of the A guys don't. One up sailing with a kite I guess you have to, so you'll just have to single ratchet with a cleat (http://www.ronstan.com.au/marine5/product.asp?ProdNo=RF46121)

Tacking / Gybing is done just the the dingies boys do. Move into the centre, without turning either direction. As you pass through the eye of the tack, flick the tiller around the back and catch it in the same hand and move to the new windward. Get the boat moving, yourself in position and then swap the tiller and main sheet into the correct hand . The trick is that you complete the second part of the tack "back handed", sounds tricky but have a look at how the laser guys do it.

There is one more thing to consider for centre sheeting, that is if you have a crew that takes the sheet, they can take it through the tack. We have been doing this for the past 5 years and it is clearly faster, it simple shares the workload of tacking the boat. The only issue is that the crew needs to pass the sheet around the back of the centre block during the tack to avoid the sheet getting twisted up.

It's worth noting that I had this conversation with allot of very interested top F18 sailors at the world titles this year including Cohen (the world Champion), but my conclusions is "try it, if it works for you keep it".

Sorry if that is long winded but I've tried to cover all the common questions.

Oh and Re the actual thread... Clearly I'm going to say Viper but as long as you'r on the water, keeping the class strong and going fast I can't complain.