you want to raise the copper level very slowly usually within 4-7 days. With that being said, cupramine recommends using a total of 40 drops for 10.5g tank to achieve a .5 mg/l (inital 20 drops and another 20 drops 48 hours latter; 4-7 is best).
But you have to test while doing so to make sure you do not overdose. test with a hanna high rage test kit or a seachem one. (API will not work correctly).
If you dose only half of the recommended that will put you at around .25 concentration which will not be effective against ich or velvet.
What fish are you treating?