In the last post of the instructions with pictures (which was copied to
there are several steps with two pictures.
Madgrizzle and I are recommending the one with two crossmembers, but in the past
you have argued that one is enough (that the top beam provides enough support to
not need the other)
I think that the extra support, and ease in squaring the frame, and the extra
diagonal bracing make it worthwhile to just add the extra board (the verticals
are still going to be an optional step)
If the decision is that the default is two, then I will simplify the
instructions to only show that case.
If the decision is that the default is one, then I will duplicate the design
into two sets of instruction, the minimal single-crossmember, and the advanced
with two crossmembers.