Hi Andrew, here's my take on your question of the mast breaking. My opinion is that your mainsheet tension while having the spin up will have more effect on supporting your mast than your diamond wire and spreader angles. Sp by straightening your mast, but making sure that your main sheet tension is on with the spin up, your mast should be supported no problem.

I take it you are trying to power up your rig? One thing i do note though is that i think your battens 3,4,and 5 counting from the bottom needs to be flatter/stiffer. The draft in that section looks a little too far forward as well. This may not power up your rig, but it will make your boat sail more in line with the concept of a pre bent rig. I used to have a A class with a set of sails where the battens was too soft for the sail and every time i cranked on the downhaul, it made the top of the sail fuller rather than flatter and powered up the boat rather than depowering it.

Hope this helps