Handy little tip for those who need to create their own tesselated Symbol Fills.
The crux of the solution is to make suitable alignments in step 5, which will be invariably tricky depending on the amount of lines are available to connect, and their position.
And I guess that apart from removing the construction lines, you don't even really need step 6?
Still, a good tip and one that I'm sure will be copied into the Tips & Tricks section.
Cheers,
Link.