Stephen/scm2000,
Actually this "discussion" has been very useful because it demonstrates that it's impossible to agree on safe techniques that significantly improve FE. People have vastly different opinions on what is safe and on what constitutes a significant improvement in FE - and worse yet an individual's opinions in both areas may change with time and experience. I know mine have.
IMO the best approach is that used on cleanmpg dot com (is it OK to refer to them here?). They simply lay out a menu of different techniques for people to try. And emphasize that the methods should be tested in a safe, traffic-free location the first few times!! People can decide for themselves how safe the techniques are and how well each works on their particular vehicle for their particular driving program. Simple, no fuss.

John

2006 Insight MT
2003 Subaru Outback
1999 Honda VFR800