Lotions are a lot of trial and error. Butters, oils and emulsifiers, silicones etc make huge differences. I have at least 20 deli cups of trial lotions and 3 matched what I wanted to accomplish. I was wanting a nice whipped emulsified body butter, a milk lotion and an everyday lotion with shea. Two do not contain shea I love Avocado butter in lotion.
If delving into lotions I would get a good gram scale and make very small test batches. If possible get in some small amount of a variety of emulsifiers and test to see which you like. I like Creammaker Blend from Ingredients to Die for and a blend of BTMS and Polawax for another.
What the others are saying. There are a huge number of possible ingredients you can use, an infinite number of variations in the amounts of the ingredients, and so there are no standard proportions. Do you want a heavy cream, a light moisturizer, a medium textured lotion? Do you want a powdery feel upon dry-down, a greasy feel, or somewhere in between? Do you want a non-oily product or one packed with oils or butters? Are you okay with silicones and other "non natural" ingredients or do you expect your products to be "all natural" (whatever "natural" means to you)? Are you willing to use preservatives and chemical emulsifiers (absolute requirements for safe, stable lotions) or do you expect to make a lotion without either of these ingredients?
Susan at swift crafty monkey is the go-to person to learn more about this.