Fred,
I have twin Yamaha 150's on my 2530. They work just fine!
In protected, calm water, I had my 2530 to 43 mph at 5600 rpm. Slightly less than half a load of fuel and three men onboard.
I think you are right at the rated max HP for the transom if you go twin 250's. You will go like a bat outta (bleep) with twin 250's Fred!
Mind you: your fuel burn will be off the chart Fred, but you will be hauling A$$ :roll: :mrgreen: :roll:
I could never use that much speed offshore. We don't have many FAC days running offshore for Tuna. Where will you be fishing the boat?
Perhaps split the difference and look at twin 200's?
Happy shopping!
Kevin G.