It is very slightly soluble. It is only 12.78mg per mL.. So when doing a cold water extraction there will be VERY little APAP left over in your solution.. Using colder water also helps keep the APAP solubility to a minimum. When you do a CWE, all the left over gunk is the APAP and the hydrocodone is suspended in the water..
It is ideal to use as little water as possible, since hydrocodone is soluble about 63mg/mL from what I came across.
So you really don't need much water at all. WORST case scenario you would have less than 50mg of acetaminophen in your final solution. This is practically nothing and will not hurt you. APAP is only dangerous once you get over 4,000mg daily.
The OP specifically stated he didn't want to IV it. CWE's are meant for oral use. Although, you could potentially take your hydro/water solution and evaporate the water. Then you'd be left with basically almost pure (assuming you did it correctly) hydrocodone crystals.