I did mine last night and drove 5 miles past 0 on the DTE and mine only took 33.9 gallons and it filled to the neck. I still had to do the clicky clicky about 4 - 5 times to get it filled to the neck. I also ran 1/4 fuel line from one vent to the other to keep crap out of them.

 

I did the mod yesterday...what a pain in the butt on gravel...anyway, I left for a trip today and think I had a couple of gallons in the tank when I made the station.
Took 34.7 gal after clicking it a couple of times.
I made about 120miles when the needle came off the pin in the gas gage..nice!
Picked mine up from Diesel Max. Their customer support is GREAT!!!!!