Yes I meant you won't have the silencer in your hands for probably six months or longer. IF the dealer IN YOUR STATE has the silencer sitting on his shelf then you MIGHT get it in your hands in 3 months. But that's a big if.
My first transfer took 6 months. The second took 12 months.
So basically you have plenty of time after figuring out which silencer/caliber you want to save money and find a host firearm.
You are right, the .40 would not be the most ideal caliber. I would get something more common that you could use on more guns.