All I know is that I have been Shooting Contender Handguns since 1982, and the method you describe about floating the forend has worked well for me.
I have used Hanger Bars, and Washers to float the barrels, and both work and serve the intended purpose. I think that if the forend is not contacting the barrel along it's entire length is what is making the difference.
When set up right, on certain barrels I have actually never had a point of impact shift when shooting off of a front rest, bipod or shooting sticks. However that is not true all the time, but rather with certain barrels I have had.
In addition to using the hanger bars or washers I generally also sand out some material from the forend for a little more clearance. This way the forend is not contacting the barrel for the full length of the forend but rather contacting the barrel in two places with equal amout of contact.
Larry
