if that 5/325 was generic then it probably wasnt really 5/325 because the dosage is never consistent with generics. I wouldnt waste my time with anything lower than 7.5 for the fact that all the acetominophin that adds up (the 325 number) is really bad for your liver.
My girl got some cough medicine that was from her friend from India. This stuff said 13% codeine. I used to drink about two table spoons and was feeling nice. Just as nice as taking a 7.5. Its not that codeine is weaker, its a different molecular structure. I used to take codeine pills when there were no percs around and they worked well for me. I never banged dope into my veins so I didnt have a tolerence issue either. I only snorted it a few times.
The best bet would be to try to find someone who sells the Percs that arent mixed with acetominophen ...That stuff kills your liver....(Roxicodone is the brand that just has oxycodone in it). I knew a dope head who would sell them to me and he would buy bundles for himself. Those were the best but they are hard to get around here. He used to get everything. Even 40 MG morphine pills.