You certainly will want to have a pro do this for you for many reasons. One of the big reasons is if you do not get the insert in properly, you may create an air leak that will cause your engine to run lean. This can and will over time do some heavy duty damage to your piston.

You also want to be very careful with the jug gasket. The same applies regarding the air leak, only it is more related to a primary compression leak. You also want to match the thickness of the old gasket to the new gasket material if you are making your own. Variation in the gasket material will change your port timing. It only takes a little difference to change the way the engine runs.

Good luck!