Practice will improve your game more than the type of club.

If you learn to play with blades then you will play better with blades, if you learn to play with game improvement irons then you will play better with game improvement irons............no matter what your hcp.

Connecting handicap to types of irons is often a mistake for many people. I would suggest going to a demo day around your area and trying every single club in the Titleist line up. By trying every single club you will be able to seek out the one model that provides the most confidence for you on the golf course. For example, Zach Johnson plays AP1's as some of his long irons. His handicap is probably around +6 or so therefore making handicap and club type unrelateable.

5 or bellow blades, above that just what ever you want but it is not all about your handicap just play your own game!!!!!!!!!!! Do what you think is right!