Generally, I would think it's a bad idea. The vet visit, and first shots are an opportunity for the vet to examine the kitten, and make sure it's healthy. There is also the chance you may give the wrong dose to the kitten.
Personally, since I have no formal medical training, I'm not comfortable giving my kitties ANY shots unless it was an emergency (epi-pen type deal). What if something went wrong? What if I gave them too much? What if I didn't inject it right or didn't give them enough so its not effective? I wouldn't want that on my shoulders. I'd leave it to the Pros. Also, I agree it's a good chance for a vet to look them over for over-all health.
I like most cats better than I like most people. I'll try to be nicer if you try to be smarter.
I personally would never give them at home, especially to kittens. Harley's "breeder" gave shots at home and he still got parvo. According to the vet, the vaccines are easy to mishandle. If they aren't kept at the right temps. they can become ineffective.