I never done a CWE on hydrcodone, but have performed many on the OTC codeine mixed with either ibuprofen or paracetamol tablets that are available in my country. When performing a CWE I tend to use anywhere between 1.5 and 2.5mL's per tablet I am extracting. I would only use 2.5mL's on extractions involving a relatively small number of pills, because the more liquid you use the more APAP comes through.
You can use not enough liquid as well though, you can't have the mixture too gluggy or it wont filter well, the amount required obviously varies with the size and contents of the tablet, I am not familiar with what you are using so I can't advise you on it. Also, there is bound to be a certain amount of losses during the process of the extraction, I am of the opinion that using not enough water can increase these losses. It stands to reason that the filters etc. will soak up a certain amount of your solution, lets say for arguments sake this is 5mL, 5mL loss out of a 50mL solution is 10% of your dose but the same loss out of 150mL is less than 3.5% loss of your dose. Keep this in mind when deciding how much water to use, but don't use too much in an effort to try save every mg or you might find that solution is cloudier at the end than you are happy with, and having to run it through twice obviously increases losses.
