trust me, even in Australia you need protection, but from the sun
I thought I could get away with it but now I look like a lands rights campaigner
Plan on a bimini at least, but it will be free of the cabin which would be too low to adjoin to unlike the larger boats.

As too tiller and wheel Ive a monohull, and her wheel steer can exert over 800lbs force, She has a wheel because she needs it, a tiller of the same force would be 22ft long. If you dont need a wheel tiller arrangements will be cheaper to organise, same for autopilot which frankly if you are doing it right you should need a lot. Price autopilot for tiller steer and wheel steer boats some day. Figure out the weight of an Edson pedestal, its heavy! If I had a choice I would go for tiller even if it meant two or three of them, but I dont.

At one time people were talking about a pop top for boats this size, which seems ideal. As long as you can stand up to cook, and maybe shower in some simple arrangement sitting in the cabin while at sea should be ok. I dont have any dimensions but it looks like you can stand in the weather hull. Steinar already made some concessions with more vertical glass, and that probably makes better use of interior volume too.

At the marina you wont care about the windage now you can stretch out a bit, and the height of a pop top is handy. But a pop top will weigh more and be a bitch to build. At one time most small boats were 4'-6" inside. I think at the very least I would plan on a very large sliding roof hatch, perhaps even double or more width, then a small dodger with the opening to lee.

Keep the interior flexible, cabinet fix the galley head and shower, use an alcohol stove, you dont have to organise special crap just places to pass out and places to sit and sponge off the guests drinks. Unlike sail boats you dont have complicated shapes to cut out where custom seating is the norm, your base inside is more or less flat and the sides of the cabin are regular. Maybe you already have some pull out sofa beds, you just might have to be a bit careful about damp over time.

Protection from the weather is more complicated. I dont know what Rob has planned for the decks but if theyre more slatted at least they will drain quickly. If Wharram cats are anything to go by, many of them ended up with permanent seating positions in more enclosed areas that were smaller and better protected with adequate fences and sometimes a cuddy. The central space to operate the boat is to lee of the cabin where it has some protection from sun and wind. But you can still man a watch from inside the cabin, and frankly many mono sailors do just that. With todays electronics you can keep a weather eye on the situation and besides, you wont survive long out there especially in Norway and I suspect that colours Steinar's money a bit.

Really the 40 looks about the minimum boat to have much in comfort inside and be a capable safe coastal cruiser, with longer adventures with some judicious care. Id reckon she depends a lot on being light weight so that needs some respect.