My formula for 480/500ml development tank:
7.5ml syrup -> 480ml: Dilution H, 2x development time of Dilution B, good for one 36exp roll
10ml syrup -> 480ml: Dilution E, 1.5x development time of Dilution B, good for two 36exp rolls (I know it's a bit short of suggested amount of syrup, but it works!)
12.5ml syrup -> 500ml: Dilution D, 1.25x development time of Dilution B, good for two 36exp rolls
15ml -> 480ml, Dilution B, good for two 36exp rolls
To measure the syrup, you can buy a Mortrain/Tylenol for kids in grocery store. It comes with a small measure cup with marks of 5ml, 7.5ml, 10ml, 12.5ml, 15ml. Perfect for the purpose.