Dick, You have mentioned advise from Salvation Army tutor, Alf Edwards,Allan Atlas and Alistair Anderson and I have to say that I find the the instructions in the SA and Alf Edwards tutors somewhat dogmatic.."right arm/hand"..."straight line"...
Allan Atlas has made a more versatile and very substantial survey of bellows technique but I mean he too is missing some points, namely the mechanical and ergonomical background which actually is (or ought to be..) quite selfevident and which decides what may be done to make bellowsing both as easy as possible and as expressful as possible.
Many occasional circumstances decide what method is preferrable for the moment...type of music, the actual piece of music, idiom, individual performer, type of instrument, playing sitting or standing, solo vs group, way addressing the audience etc

There are also individual habits and various means handling the instrument and not least various "handles" that decide what actually can be done regarding bellows control(the original outfit for the English with traditional thumbstrap and finger rest definitely is NOT very purposeful generally but of course may be suitable for particular situations)

I have tried to illustrate some of the views on this at
http://www.youtube.com/watch?v=wIpE38VoY08&feature=relatedhttp://www.youtube.com/watch?v=0c1aIVNC_84&feature=related