yeah the tm24 is the right version you should buy and is what others have used with great success.
Its the flatside version which creates better throttle response due to the improved airflow throughout the carb.
Theres a couple options for intakes.
It is certain that intakes that are designed to fit Minarelli Scooter Engines will fit the gila kit.
Also, treatshq use to sell a 24mm intake (he does the 21 also) that comes with a nice rubber coupling and two hose clamps for ease of installation. This is the route I took.
Also, if you can weld. Its very easy to make something of your own. Use the intake that came with the kit as a base for your fabbed one and then get some metal piping for the store with the right bend to weld on there. Should be fairly straight forward and the route I WOULD HAVE done for a completely custom and flush look for my ped if I had a welder handy.