Building a cockpit liner mold, how do I support it?

As the title states, I am currently working on a plug boat. I already have the hull mold and now have a bare hull with stringers I'm going to drop a deck and a fore and aft bulkhead above the deck and finish the sides of the gunnels. I'm then going to use that as a plug to lay up a mold and then I will have a mold for a cockpit to just drop on the deck in the future.
I'm trying to decide how to support the mold and prevent it from warping (the boat is 24 feet long and 8.5 foot beam). The cockpit mold will probably end up being about 17 feet long. I also need to add some type of framework to the mold to make it serviceable. I thought about building it onto a 18 foot long boat trailer.
I would love some input.
The hull is similar to a 24 Aquasport
Thanks

 

Could you show us some scheme of how you want the deck and the cockpit?
Sometimes the deck, the bulwark and the lower part of the cockpit come out of the same mold.

 

I'm sorry my terminology isnt perfect. I'm essentially looking to make a 5 sided tub that sits on the stringers that will provide a deck , finished gunnels and fore and aft (buklheads?)

 

Essentially a mold like this but no raised step on the front deck. Juet a simple drop in liner

 

Anyone?

 

Any sketch about what you intent to do?