I prefer shorter strips. They have several advantages. It is quicker and easier than full length strips. I have quite a few full length strips left over from a previous build, but I avoid using them.

There is an argument for using a full length strip at the sheer, but even there it certainly isn't essential.

I have built 4.5 metre kayaks from 3 metre and 2.4 metre strips. I built my 5 metre kayak from 1.8 metre strips. Most of the joins are almost invisible.