I mix D76 1:3. That means I mix 8 ounces of D76 stock solution with 24 ounces of water to make up a total of 32 ounces. When I use it 1:1, I mix 16 ounces of D76 stock solution with 16 ounces of water to make up a total of 32 ounces.
I mix LPD 1:4. That means I mix 10 ounces of LPD stock solution with 40 ounces of water to make up a total of 50 ounces.
I mix Dektol 1:2. That means I mix 16 ounces of Dektol stock solution with 32 ounces of water to make up a total of 48 ounces.
I don't know if it's "+" or ":" that's correct or even if my proportions are correct. I only know it works every time, 100% of the time, to my complete satisfaction.
(I also mix 1.5 ounces of 100% agave tequila with 1 ounce of Cointreau and 2 ounces of fresh squeezed lime juice to make a killer margarita. I have no idea how you write that as a ratio. I just know I need one right now!)