This question is a very old post, but I'm going to go for it anyway.
I assume you mean Masa Harina or Maseca masa. I use Maseca Nixtamasa. This recipe gives me 100 % consistency (with corn tortillas, gorditas, and puffy tacos- same proportions for all 3):
2 Cups masa
1/4 teaspoon salt (whisk well before adding water)
1 1/4 Cups water
Stir together with a serving spoon size spoon. You'll have some "stray" masa at the bottom, under the dough ball, so at that point, start incorporating it with your fingers as you knead the dough a bit.
Roll the dough into balls (size varies according to what you're making) and place into a gallon size freezer bag to keep dough from drying out.
I use a press (Tortilladora from Amazon). (I keep mine hanging on the wall, but it's used a lot.) Cut the "zipper" off of a smaller freezer bag (quart, I guess), then cut about an eighth inch off of each side. Open it up and lay one side of the baggie on the press. Put a ball of dough on the plastic, lay the other side of the baggie over it and press a little with the heel of your hand- then press the first time with the press. Open it up to see where your masa is positioned on the press. Center it and really press again (harder). How thin you get the dough depends on how big the ball was. You kinda have to play with it.
My comal is a De Buyer carbon steel crepe pan, set at about 4 1/2 to 5 on a ceramic glass cooktop. (The temp on your range may vary) I press the next tortilla while the previous one is cooking.
Hat tip to Lisa Fain, who has homesicktexan.com blog, for the recipe. It's a beauty!