Yes timer methods are interesting but at this point I'm not going back to sleep after 5-6 hours if awakened so I'm back to trying to fix my sleep again, sigh.
edit:
Another following the pattern last night: some brief wakings with recall which I ignored and went back to sleep (I think), followed by a waking at about 6 hours with decent recall (somewhat fragmented this time), and I can't get back to sleep after even just fast keyword recording. Tried for a early afternoon nap, and within about 20 minutes I started getting HI, the "falling" feeling, and some WILD 'noise' (ragged breathing mostly). But despite attempts to "sink into it" the sensations subsided and I was then wide awake. Argh. WILD seems beyond me for some reason.