I don't pipe in much in these forums, but this is a subject that's been of interest to me and many of my colleagues here in Los Angeles.
After many years of playing large equipment I shifted (after a LONG layoff) to relatively small equipment for big band (8310Z Shew Yamaha and Schilke 13A4) and found that things got easier for me in that setting, but my range-- always an issue-- was going nowhere, and my sound was pinching as I ascended. Further investigation was needed and after consulting fellow pros here in LA I discovered that some rebalancing was in order.
I picked up a Maggio book at the suggestion of a rather well known man and wife trumpet team, and something very interesting took place. I switched my mpc to a CG Personal (a similar rim but a giant throat of #22-- hardly "efficient") and a large bore MF Horn for these exercises and others: essentially a Gordon type setup and after two weeks it seems that my problem was less a matter of efficiency but developing relaxed, flexible chops that helped me translate the sound concept in my head to the bell of my horn, that being a fat, solid sound in all registers. When I switched to a smaller set up, I didn't have to work quite as hard, but the larger one doesn't tire me out as it once did; more "stuff" is vibrating and when proper air is applied, the chops can hang longer.
Without reservation an efficient setup will help most folks, but what goes on behind the horn, proper breathing and a routine that allows for maximum vibration, has brought me far better results and an ability to switch equipment to match the job at hand. I hope my little anecdote is helpful.
Ed Mann
MySpace.com - Ed Mann - 51 - Male - LA, California - www.myspace.com/jazzlips