I love the way you tweaked Walls's subbing to use grocery store ingredients .
Also, this has been touched on, but if you are a chemistry newbie , you may have missed the one nifty thing about water-based solutions. 1 ml water = 1 g water.
Although I like to use acrylic gesso thinned down to the weight of light cream to practice coating, gelatin is certainly easier to get. One caveat: it's good for practicing with your tools, but it doesn't bear much resemblance to a real emulsion. Most of what you learn about surfactants and hardeners won't carry over to the real deal, so don't worry too much about those details right now. Also, % gelatin as it relates to viscosity is temperature dependent and viscosity is the one real thing to practice with your tools. It determines how fast the emulsion spreads out gaps. 10% is only a starting point. If you want to practice coating with things at room temperature (easiest and most consistent in the beginning), play the amount of gelatin up or down in order to get a solution about the thickness of cream.