I like to make the fore end one with the barrel. I like to pillar bed the fore end and then full length bed the fore end to the barrel with the fore end NOT pushing on the frame - so the fore end is tight to the barrel, but with a small gap to the frame. This will result in a barrel that is a little "sloppy" feeling when open, but it still locks up tight when closed. This way I can shoot with the fore end rested in my hand, use a Bi-Pod or off of bags and still shoot tight groups. If you need to "float" the barrel with an O-ring, then you will probably have to shoot off of the frame, other wise you defeat the use of the O-ring. Of course every gun IS different and you really need to find what works best with it. I think you should always start with the way the guns comes to you. If it shoots to your expectations, then you are home free. If not, then there are several different things to try, including the O-ring. The O-ring is simple, cheap and reversable, but if it does not preform to your expectations, then you need to try other things.
Good Luck and Good Shooting