Nope, no idea on starting percentages. Each of the flavorings I linked are different strengths.
I like mine with no lime and extra rum...In fact leave out the strawberries and add more rum would be even better.
If it were me, I'd make a strawberry that tasted acceptable, then I'd work up a separate batch of rum until it tasted acceptable. Then I would start experimenting with mixing those batches together and adding dashes and tweaks of other stuff. If I managed to get something to work, I'd go back to my notes and reverse engineer all the different stuff in it to extract a recipe.
But it takes me a long period of time to get my recipes because I'm exceedingly picky. (And sometimes I give up and move on to the next idea because I get bored with what I was chasing.)