Lets look what is the difference with european Union varroa research solution and with
Safarina's recipe is egual 300 g sugar + 300 g water + 18 g OA = 3% solution for 14 hives.
I told 100 + 100 + 7,5 = 3,6% for 5 one-box hive or for 3 two-box hive.
3% is ok, because switcherland uses 2,5% OA. Some uses 4% solution.
If you spray OA on bees on boath sides of combs, recommendation is 3%, what Safarina says.
I would say that boath recipes are the same. In bigger volume you must cast away more sugar.