It's perfectly fine to rack into smaller containers. In fact, that's how you're supposed to do it.
Carboys are cheap, so if you're doing a six gallon kit, you could get some 3 gallon carboys, as well as some 1 gallon carboys. I don't recall where I read it, but you can expect to lose about 10% of your wine at each racking. (On my first batch myself, so I'm giving you book knowledge, not real world experience!) If you have 6 gallons on lees, you'll rack 5+ gallons.
I'd rack to a 3 gallon carboy, and two one gallon carboys. As you keep racking, you could keep topping off with one of the one gallon carboys.
It's also ok to top off with a commercial wine that is close to what you're making. Better than water, or air. :)
Cheers, Will