Andy it is too easy to assemble your boat with 6hp outboard, and it is enough power to plane with 2 adults on board. But it would be a perfect hot rod with 15hp.
I started with 3,8mt sib with 10hp, then i bought 30hp 2 stroke, then i find a zodiac 4.8mt, and now 30hp seems a little weak to me for 4,8mt boat. Looking for a chance to find a tiller 40 hp. I mean the set up is growing up unavoidably
Be sure to use it at recomended pressure.
Here is a video for assemble for similar sib.