tcasblue,
At first read, that article looks excellent, and expounds a number of issues I raise during type training. I'm going to read again in great detail. It is one of Dave Thurston's (Design for Flying book) which I own and fly, and it's a very draggy glider!
To further one's understanding a little more, read up on helicopter autorotations. Yes, Helicopters glide, just not far! But they're very controllable, and indeed a lot of fun to glide, you're just not doing it for long! BUT, there is a limiting "height velocity curve" for every helicopter, as there should also be for every airplane. As with helicopters, you can get an airplane into a combination of height, and speed from which a successful glide landing after an engine failure would not be possible - and no one tells pilots this alarming fact. It's up to pilots to figure it out for themselves, and avoid that regime of flight (without being told what it is!). But helicopters have an added advantage in the glide and flare over an airplane. Helicopters store energy for the flare both as airspeed (which may be held faster to store more energy, as a plane), and as extra rotor RPM, as helicopters can be autorotated with rotor RPM greater than that permitted for powered flight, so as to store energy in the extra rotor RPM, to be used during the flare, which airplanes cannot do.
This is why I train, as John's passage later validated for me, to store extra speed in a glide. Unless you need to stretch your glide to make it to the coast, or over the mountains, choose a spot closer, make no attempt to stretch the glide, and get it down well. With the extra speed stored, you can either spend it to prefect your flare, or dump it out at the last minute as a sideslip, or more flap extension. 'Worst is you land long. 'Better than landing short on a forced landing!