A hat is generally about 20-22" around, so you can see there might be a problem if you use a needle several inches longer. However, there is a method called Magic loop or a variation of that - Modified Magic Loop
- where you can use a longer needle than the item you knit. I make hats with a 24" using the modified ML, so you should be able to use a 29". That's a good versatile size for most things btw, you can make throws, baby blankets, shawls and adult sweaters with it.