You really think so? With the vang loads you need to use to go fast upwind in 15 knots plus, bending is inevitable. You will get a longer life in you nurse the section for the first couple of months, but you really shouldn't need to. You should be able to put a new mast up and go sailing without having to worry. Bending back doesn't really work. You can make a mast look straight again, but it returns to it's banana shape as soon as you put any load on. Would a sleeve fix the problem, or would it alter the bend characteristics too much? Carbon is the ultimate answer, but it is a long way away.