Second aggie suggestion about getting both if possible. We use the 2 reel tanks all the time with one roll of film. You need to be sure to use enough chemistry to cover which is at least 10ounces with the patterson reels and that the reel is pushed down all the way to the bottom of the spindle. People have been known to forget that and end up with uneven development. Of course you could also just put an emplty reel on top.
You will find that there may be times when you will need more than just 2 reels. ALthough you can reload a patterson reel if it is damp (at least the newer ones) it can be difficult.