Bam: Welcome to the forum.
First rule of thumb for all fresh fruit wines, More is not better.
Pounds per gallon of fruit, Particularly Peaches is going to depend on the fruit variety, sweetness ripeness etc......
I have several peach trees in my yard, two of the trees are productive. One tree has yellow freestone peaches that are very juicy and sweet, the other is a white flesh freestone peach that are sweet but on the dry side. I used 5 pounds of fruit per gallon and it's OK, but not all that peachy flavor that I wanted.
I would recommend, using your hydrometer, take an SG reading of the fruit juice itself as you mash them up (just juice, no pulp) This will help you with the amount of sugar to add, to reach your target ABV. Which I would keep at or below 11%
Peach wine does take a lot of peaches per gallon. My guess is however that 2.5 pounds per gallon isn't nearly enough. I would start at the 6 pound mark and work my way up to 8 if needed. When I do this, I make my recipe for a five gallon batch, and usually end at a 6 gallon batch.
You could also stick to your gutt feeling, you can always make changes i.e. add more peaches during fermentation or sweeten back with a frozen Welch's Peach flavored grape juice (from your local grocer)
Edit: More peaches should give you more must, more must equals less water. Again............. More isn't always better........ It might be for flavor, but don't forget balance.
Edited by: jobe05