Understand that there is little up-side in fluting. It is expensive for one, and if you are using a button-rifled barrel, it is very ill-advised as it is a mechanical form of stress relieving. It affects weight very little, and unless flutes are cut with absolute precision, any inconsistency can lead to warping with heat. As to heat dissipation. I think you are just as far ahead to use a bead-blasted finish or paint it matte black.
Having said all that, many guys have their barrels fluted without a problem, but you are talking about a top-end gun and investing good money and time into it. I would hesitate to throw-in any variable that may add to your inability to make it work consistently , since you will be dealing with a really short barrel life as it is.
If you want a really light contour, go cut rifled Chromoly steel.
Have you decided on bullet weights and twist? if it is to be a varmint rifle, lighter bullets are what i would personally use. Bullets in the 65-70 grain range will be flying out of there at Mach 4 plus. Use a slow twist! 13.5 is good, Also, you do not need (or even want) a really long barrel for light bullets there is no advantage and can even detract from velocity.
