Hey Jesse,
I have converted mine to trips. It looks pretty awesome. I had a custome floatation bracket made for it and had the transome completely rebuilt and reinforced to hold triple 350 4cycle Mercs. I've yet to get the Mercs. Saving up the $$$.
I had to rebuild the transome due to the stock brackets had started to cut into the transome and the transome started to rot. As far as needing to reinforce I would. The average 250 outboard weighs 700-800 lbs plus the and extra bracket or new bracket is another 100-200 lbs. then you have to figure the added stress of the extra power.
Good luck and have fun with your project.