There is another option. Put a generator
inboard, under the hatches mentioned? Then add electric
outboards. The bonus is that you get a light weight power unit that will also drive domestic electrical equipment
and an outboard
unit that is not readily sold on the open market. With the right kit your domestic batteries will allow for some manoeuvring to get you out of the marina on a quiet day and you can then crank up the genny or raise sails
to suit. Have a search on t'internet to compare prices for each build.
manufacturer's sites should give noise levels. I'd be a little worried if you can't tilt the props clear of the water
. I get an extra knot
or more by lifting the drive leg.
And there's always something to knock your prop on.
Have a good look on Ebay too, there are some good deals on Outboards from people like you, changing up or down for the new or old boat. And you're fitting two. They don't have to new to be reliable. You should get a good price
for yours too.