I have not found my PIV to run much different with gas in both tanks, I have one 10 gallon saddle tank, top end was the same whether I had 33 or 43 gallons. I have found that the biggest factor for me is to get the weight in the back of the boat and out of the front compartments, so Ill run my plugs up front and plastics, jig, and weights in the back. I had an 02 Jag before this PIV and have found this to be the biggest difference between the two, it didnt matter how I put stuff in the Jag, it ran the same top end loaded, I think thats because of the rear tanks in the Jag. A total of 43 gallons in the PIV has been enough for me, the longest run I make is about 90 miles round trip. Mike