topping off QF

OK, I just posted about the adding clean urine to my qf .Deige was very helpful in reassuring me about the fact they cant ask for more than 2oz but after reading this post I am thinking it might be safer(due to the amount of samples coming in right at 2oz from everyone thats subbing) to top off the qf with either clean urine or old qf approx. 18 months old....i cant afford another new qf either.
The reason I dont just go with an entire 2plus oz of the clean urine is I have a 3 and a half hour drive and an undetermined waiting period between paperwork and taking the UA so I am a little worried about the urine fermenting or smelling weird as the weather is going to be in the 70 degree range.
So which would be LESS risky ... top off good qf with 18month old qf OR top off good qf with clean urine .
My test is tommorow 3-18-10 Help Burnt toast,FBR,Killerweed420,Deige or anyone ?
I will post my experience at the lab and results whenever I find out.
Still paranoid.
Thanks in advance.

Either clean urine, if you're sure its clean or well water should be fine. Depending on how dirty you are, it might work to just add a little of your heavily dilluted urine.

My gf is clean except she took 20mg to 80 mg once a day of celexa for about 3 years until xmas 2009.Nothing since. I have no access to well water that i know of so maybe I should still trust the exact 2oz portion of qf,what would you do ?
Thanks for your help.