I did a search. I did find information and layout of the 26 but not the 21.
If you take out the wall between the steering station and the saloon, you should be able to either lengthen the V-berth or adding a small wet head. The days of crapping and peeing over the side are long gone. CHUCKLE
Share your plans about your proposed galley area with us?
The bilge is how deep in the saloon area excluding the engine area.
Tell us about your fuel and water tank.... size, material. One house battery, one start battery? Obviously, a generator is pretty much out of the question. A/C not possible either.
I totally agree with Pete's comment, "Do go nuts." with the modifications.
I have a lot of "over-kill" on my AT34 or as I tell folks, "I have put a lot of perfume on the pig." I "think" I am finished with my internal 'mods for comfort'. It is time to renew the canvas to its final design, upgrading my electronic to the previous century.
Time for you to determine the design of the house.... and also, what goes inside the house and where it is placed. But first, construct the house.... leave the internal structor/walls bare.... You will have lots of wire to pull and place. This is much easier to do without the walls. Consider a conduit for the longer runs... Obviously, no splices internal to the conduit.