Can't say I have any personal experience with an outboard on the Vega. Check out the photos at
SY Rebellion - Home for an interesting idea about mounting for sea work. Scroll about three fourths of the way down.
We are going to replace if/when the old MD6A finally goes and I'm tired of working on her. My preference is for a 4 stroke rather than a tempermental two-stroke. Yamaha makes a 9.9 HP 4 stroke which can be purchased with an alternator (10 amp, I think).
In any case, when/if the old MD6A goes, I'll beef up the stern and transom with glassed in 1" marine ply. Although I noticed that there are two "studs" glassed into the left side of the stern, I don't think the Vega was built with an outboard in mind. Again, having never met Mr. Brohall, I could definitely be wrong.
Best of luck.
Jack
Bella - V2620