Neils build will be the second or possibly the third level of building Shane. To answer your question logically, it depends on your skill level re understanding boat, aircraft or whatever construction.
In a beginners kit you will find most of the bits cut to profile or sizes that basically require gluing together so a rudimentary plan is supplied that doesn't need the bulkhead shapes to be drawn out. Same applies if the shapes are printed onto wood to be cut out by the builder.
Next level is where you are scratch (Or semi-scratch depending on definition) from a plan that requires you to obtain the materials yourself and transfer the outline shapes of the detailed bulkheads etc. usually shown on the plans as separate profiles of each one. Model construction details may be shown.
The more advanced plans only show the basic lines of the profiles normally superimposed onto each other around a single vertical centre line, with the stations of these shown on the side elevation of the hull. Construction details are not normally shown and this type or the builders plan is where I think Neils boats start.
Plans supplied on this side of the pond used to have a star grading system from one to five, one being basic and five needing a more advanced builder not needing a "glue a to b" and no, I'm not mocking, everybody needs to start somewhere.
With regards to the plastic hulls you and your Friend have, if you can obtain copies of plans for what you have, at whatever scale or detail level, measure the lengths of your own hulls and take the plans to a plan printer (Think it's Kinko's in the US of) and get them to scan and reprint to the same hull length. Isn't electronics wonderful? In the past, it would have been a big sheet of paper, a ruler, multiplication tables and lots of graphite.
Regards Ian.
And don't be fooled, Neil knows how to build longhand too.