I have the Solerno blood orange liqueur and will have to try it in a margarita. I have cut down on the simple syrup over the years, but can help to balance out the fresh lime juice.
My other "recipe" is what I call 4-3-2-1 for the "parts" tequila-lime juice-orange liquor-simple syrup. Makes a nice 10 oz drink; even a little more after you shake it over ice. And it provides at least 100% of the US RDA for tequila.