One more thing occurs to me too, Andy. You have no concept of what occurs as you age, and I assure you, you will. If you think you will be able to heave as much over your head 15-20 years hence as you do now you are indeed a callow youth.
When someone says they must make allowences because of aging they are, most likely, telling you the facts. Even those oldsters who are able enough to lift the weight may not get it over their heads because their shoudler joints and other supposedly flexible components, are arthritic.
I will not bore you with how I know all this.

: One other point occurs to me - the Guillemot is not the easiest strip
: built boat as some strips curve quite sharply towards the ends.
: Shortening the design will tighten those curves, making it a little
: harder again to build... Your particular method, of reducing the form
: spacing more at the ends than at the centre, will accentuate this. As a
: first boat built with this method, this may not be what you want :-)

: Andy