27 Flybridge conversion from I/O to Outboard

[3rdday]

Hi Everoyne,
I wanted to solicit technically based opinions; I know i'm about to get my ass kicked for thinking of putting a single on a heavy 27' boat.
I have sold the outdrive on my Moesly 27 Flybridge Seamaster, and I believe Im going to get the $ I want for the Bravo 454. I have already purchased a Bracket 30" setback that will fit nicely.
I plan to repower with a single new 300 E-tec, I came about this decision based on these facts and theories;

I am doing this for economy not high speed - thus 1 engine- I DO NOT PLAN ON SELLING, EVER. The EXTRA 12K for twins buys allot of fuel.
My old set up was supposedly 310 Hp at the prop
Bracketed set ups are supposedly 10-15 % more efficient
The boat will weigh about 800 (15%) Lbs Less
Etec has good fuel economy and can NOW tell you best throttle position on the fly.
I am not concerned with reliability, it will be a new motor, and I have Seatow, two VHF, Cell Phone, and EPIRB, and overkill on safety flotation devices.
Two strokes provide power on every stroke, versus everyother on 4 strokes.
The Seacraft Bottom itself is more efficient than other hull bottoms.
I have seen other 28' with single Etec perform well , not quite as heavy but close.

What do you all think?