That is interesting. When I bought my 1988 24 offshore, the 93 gallon tank was factory installed in the front compartment and the aux tank compartment (rear) was empty. I added a 25 gallon tank and a 25 gallon fresh water tank in that compartment since then. I noticed that the boat rides better when I burn off the 25 gallons in the rear tank first. I use my Yamaha fuel management gage to know when to switch tanks. Did Grady move the main tank back and put the aux up front in the later years?