If you haven't already id go through and check the o rings and seats one by one as well... just take apart one area of the gun at a time so you don't get a mix up of parts and pieces. Take em and clean them individually and I usually grab a tiny Tupperware (we have some that are maybe 3-4 oz size) to put drops of oil in, as you clean them drop them in the oil and get them completely covered and put it back together.
also do a "nail" test on the o rings and reg seat, press your fingernail into them pretty hard, if you leave an indent they are most likely too dried up to seal or are too far gone to save with lots of oil. That's where the parts kit comes in...
Also, I usually drop 5-6 drops of oil in my parts kit where my o rings are to keep them moist... I don't know if it actually does anything... but it makes me feel better, that's what its all about right? Haha.
Good luck though, clean er' up and post some pics!