RM,
The constant aspect approach works well no matter how well your aircraft glides. If anything, it's probably easier with a steep glide angle as the aspect changes are more easily recognised when you are rapidly plummeting earthwards. The chippy did glide well and constant aspest PFLs were easy. The Bulldog had half the gliding performance which made it easier to PFL as it was more of a 'by numbers' exercise. the Tucano was a pig as it had too much glide performance and getting the height off was a problem. The Hawk is easy, again another numbers exercise.
As a measure of glide performance, you have to look at the hi-key heights required. (For those who don't know the procedure, hi-key is the overhead the threshold height at which you start the pattern). The Chippys was 1500', Bulldog 2500', Jet Provost 2500', Tucano 2500' (too high for that aircraft, so I tended to use 2000') Hawk 4500', and Harrier 12500'.
I wrote an article for the CAA GA safety magazine some time ago about the constant aspect approach. At the time, there were a couple of panel examiners who were keen to introduce it into the CAA sylabus. The stats spoke for themselves. The square pattern in GA had a success rate of under 10%. The military way - over 70%. Unfortunately, there was a lot of opposition, mainly due to a perceived veiw that it would increase the hours required to do a PPL. IMHO, the main reason for the success of military PFLs is that military pilots are required to stay in current practice - one every 2 months as a minimum if my memory serves me correctly. I used to practise far more, which meant that when I had do do one for real, it worked.
For those of you who haven't seen the constant aspect PFL, I implore you to go flying with an ex-military QFI and try it. You will probably like it. I ended up teaching an flying club instructor how to do them once when he was supposed to be giving me a check ride.