It took me about 45 minutes to assemble my Kahuna for the first time,
that included fielding one or two customers' questions at the
paddlesports shop whee I work part time. I had not assembled ANY
Feathercraft kayak prior to then. My fastest assembly time is around
20-25 minutes.

I agree with the respondent who said that having hatches would aid in
the assembly process. It would certainly help if you plan on using
the boat for overnighters.
I took mine on an 8-day trip through the Everglades last year and
hatches would have been nice.
I would have liked to have had a rudder as well. The waves got a bit
pushy on the first 2 days out in the ocean. Rudder would have helped
also with the wind hitting at odd angles. The Kahuna performed quite
well though and I was very pleased with it. At one point we had to go
about a mile or so across Whiewater Bay to get to one of the overnight
stops. The winds were about 15 to 20 mph, but were dead in our face
which made the going pretty easy; despite the resistance, the boat
wasn't getting pushed around as it was with the wind at an angle.
I had never intended to use the Kahuna for anything more than day
trips when I purchased it but it proved it's worth as a multi-day
boat. Definitely consider the K1 though if you plan on open ocean
trips.