What is the real and / or the best "agua de valencia" recipe?!

On the net I found different recipes, according to some there should be 50% orange juice and 50% cava, according to others 25% orange juice and 75% cava. And some had cointreau, some had sugar, ...

Could anyone tell me a good recipe?! Would like to serve agua de valencia for my friends on my birthday.

Many thanks, Katja

CONGRATULATIONS!!!
Here it is, the genuine Agua de Valencia recipe:

INGREDIENTS
Cava (better if brut nature, never use the Seco one): 1/2 liter
Sqeezed Orange Juice: 1/2 liter
Gin: 60 cc
Cointreau: 60 cc
Vodka: 60 cc
White sugar: two soup spoons
Ice
Orange Slices: 2 or 3 (decoration)

PREPARATION:
Sqeeze the oranges and put the juice in a big pitcher, mix it with Cointreau, Vodka, Gin and sugar. Use a long spoon to stir all the ingredients till the sugar has disappeared. Now spill the Cava, very cold, you must be stiring all the time to mix everything, but be careful! if you stir very hard you'll lose tha Cava bubbles (so you're dead). Put now five or six ice cubes and two or three orange slices (in circumference). Stir again and...you have it. Use cava glasses.

Tell me about the party
Have Fun!

The ones I heard long time ago were orange juice + cava + some spoonfuls of sugar and a little cointreau.

Adding more liquours sounds like a different drink to me. Like trying to sophisticate it through an evolution to a punch or to a "zurracapote" (where any liquor is welcome).

Many thanks, I'm sure my guests will love it! Katja