If sleeping aboard is really high on your priorities, I just wouldn't be going alloy. Even a 50 footer is like sleeping inside a rainwater tank being showered with rocks, unless a lot of insulation has been added., if you are up in the vee. I did this for many years. The smallest ripple makes alloy very noisy. On the other hand, I sleep in my 6.4 metre glass like a baby, even in strong winds. You can still hear it, but very muted.