Rolf,
I think you are right.
I even enjoyed the fairing of the floats. It took me 4 hours to get the beading on each side of each float and only 1.5 hours to long board it off each side. I then applied filler with spring steel blade in such thin coats that it took 4 applications until any remaining beading could not to be seen. I'd alternate the application between plus and minus 45 deg angle between coats when putting it on. This worked great at getting a very flat finish. This meant almost no sanding. Just a light rub between coats with orbital sander to take off any dags. The floats are undercoated and they look perfect. (The top coat will tell the full story.) The main hull will be a lot more work but only because it has much greater surface area. I realised when fairing the floats how much work I saved by taking my time in placing the foam in the mould so I was even more careful with the main hull. The real secret in getting the foam right was the building of the oven to evenly heat the foam. I tried the hot air gun method and could not get the foam to bend as evenly through the curves as I'd like. A couple of friends dropped around and decided to build the simple oven with stuff I had lying around and some ceramic heaters that I'd bought years before. Then I experimented with temperature and found the Corecell M80 foam formed its shape best at around 105 deg C. Lower and it would not bend evenly and higher , say 112 deg C, and it would tend to cup along the edges. The supplier had told me to heat it to 80 -90 deg C. It will bend at that temp but not evenly. You end up with a lot of flats and sharp curves on what should be a smooth radius. It really pays to get the foam stage right. It is so much more pleasant than filling and sanding later. I suppose it is all a part of the Zen of boat building.