How about a few pages devoted to tube fly issues.
I've recently started working with tube flies myself, and I'm
amazed (and chagrined) I didn't take them more seriously
sooner.

...any fly you can tie on a long-shanked streamer hook
you can also tie on a tube of some sort. Tubes can be
weighted as much or as little as you want. The primary
benefit is (the tube's) ability to put a short-shanked
hook at the rear end of the fly. Long shanked hooks
do (because of increased leverage) pop out of the fish's
mouth more easily, and more frequently.

Good idea. I've just started with tubes myself and they seem to offer
all sorts of advantages. I'll work it into the tying section.