A 24 Offshore is 8'3" wide, a 265 is 9' 7"wide
90 gals vs 250 gallons
A 268 Islander is 8'5" wide and weighs over 1000 lbs less ...dry
I don't think 300 hp is nearly enough for a 265 express. You will regret it
A single config will be un-dockable.
You need at least twin 200s. 225s are sweet. 250s un-necessary.
There has been discussion on here about this subject.
It is my understanding that 265 hulls changed in 2003? to flatten out the dead rise to accommodate greater weight of the new(at the time) four strokes
Hulls before then may have scupper problems if you go with V6 fourstrokes.(i'm just going by what I've heard. )
Your current choices of lighter motors are
Suzuki DF200AP (I am leaning heavily toward Zukes for my eventual repower)
Yamaha F200 (the new i4 not the old V6)
The newest (non-Verado) Mercury V6 225s ( These 2019 models are 500 lbs V6 four strokes! I have heard good owner reviews so far and no bad one's yet. I hesitate to be a first adopter.)
Evinrude 2 strokes.