I'm sure Roger will answer, but I think you'd miss some options of the 7095 by going with two 7091s.
If what you want is simply to have two separately pulsing powerheads, two 7091s would work I think. They'd pulse independently of one another, I guess, although you could try to match up or contrast the timing of the pulsing -- although you're on a fairly narrow time band there, it's like 1 to 5 seconds. If you want to alternate two (or more) pumps -- either turning one off while the other is on or ramping one down to 30 percent while the other is on -- you'd need the 7095.
Also note that if you want to use night mode, you'd need two separate photo cels, which would start to get the price of two 7091s closer to the 7095. You'd also have to press two buttons not one every time you used the food timer.
