Cockpit cushions are a simple project for any good canvas place. The most important thing is to make sure the right supplies are used. Some houses go cheap to win the bid. You want 1. Foam that won't absorb water (much less expensive than closed cell foam), 2. A scrim back that allows air to circulate inside the cover, a very good quality sailing zipper (The zipper allows you to pull the foam to clean, or dry or replace parts), and top quality cover material. White vinyl with a fabric back works great. Sunbrella gets dirty easy when you're walking on it.