If you are still faced with that question about the gap...

Introducing a gap that deviates from the profile of the form is more of a problem with the Hull,
since that would affect the performance.  
On the deck it would mean that the gap on one side would probably not be symetrical with the other side,
and this is the side you will see most.  Also it means that the shape of the cockpit would be affected.

I'm building a Guillemot and when I saw that gaps were starting to form, due to my inattention,
I started using many more staples to minimize them.  I found that I could tollerate a gap of no more than 1/8
inch.  More than that and I had an odd shaped section of the boat.

As far as the number of full length strips, I figured out my shape of the cockpit that I wanted and mocked-up
a cockpit frame that I could lay over the strips and thereby learn if the strip that I was inserting was
to be full length or not.

Joe

When I worked on a Petrel, there was a plywood cockpit recess piece. I positioned it where It seemed it should go with respect to the forms and the deck strips.  Then cut strips to fit.  You definately do not want the strips  to ride high over the forms except of course in the cockpit area where there will be no strips.  

Look in shop tips, strip planking, video #23 and you might get some good tips. 

Ed