Perhaps just over an hour at the boat and an hour at home. I'll explain.
Shoal Survivor came with Dri-Deck in the cockpit; certainly durable as hell, functional... and ugly. More than that, we found it exceptionally painful on bare feet and when kneeling to do anything engine related (lock down, pump primer, check the oil) or locker related. I saw snap-together wooden exterior deck tiles installed in a Gemini and thought "that's just plain obvious." He had used tiles from IKEA, but I opted for teak from a different source. Much the same, but perhaps the teak will last longer.
So, instead of doing real carpentry, I cheated by using these.
Nothing difficult. Do avoid working in real cold or real heat and sun; the plastic underlayment works most easily at moderate temperatures. Too cold, it is brittle. Too hot and it gets soft and may warp. I had minor troubles with a few tiles that had been left bottom-up in the sun; the screw holes didn't line up so well until they cooled. The flexibility of the tiles easily conformed to the modest compound curvature of the deck.
Given that the cockpit is well protected by a hard-top we expect minimal maintenance, but we'll add some fresh pictures to this post in a year or so.
We love the result. It feels much cooler, because we can go barefoot and because it is cooler than FRP. It still drains, it's nicely non-slip, and we can still lift it for cleaning. And it looks yachty as well, a nice deception.
And we made 3 of these from the leftovers....
October 29, 2012: It's looking a bit weathered now, but I made no effort to oil or preserve it. The foot comfort has been a great improvement and it seems to be holding up.
August 2013: First maintenance. I spent 10 minutes running an orbital sander over it with 150 grit, then then 10 minutes laying on a light coat of thinned varnish. Looks like day one. I believe this will be the long term maintenance requirement; every time the boat is hauled for the bottom, spend 20 minutes on a light sand/varnish. Easy.