Maybe this will answer your question about Fluted or Plain barrel.
This is taken directly from Shilen Rifles web sight.
Fluting is a service we neither offer nor recommend. If you have a Shilen barrel fluted, the warranty is void. Fluting a barrel can induce unrecoverable stresses that will encourage warping when heated and can also swell the bore dimensions, causing loose spots in the bore. A solid (un-fluted) barrel is more rigid than a fluted barrel of equal diameter. A fluted barrel is more rigid than a solid barrel of equal weight. All rifle barrels flex when fired. Accuracy requires that they simply flex the same and return the same each time they are fired, hence the requirement for a pillar bedded action and free floating barrel. The unrecoverable stresses that fluting can induce will cause the barrel to flex differently or not return from the flexing without cooling down a major amount. This is usually longer than a shooter has to wait for the next shot. The claim of the flutes helping to wick heat away faster is true, but the benefit of the flutes is not recognizable in this regard until the barrel is already too hot.
As far as the twist goes, all of the H&R barrels will eventually be 1:9 twist, fluted or not. Right now you need to check the twist before you buy the barrel, because there is not a way otherwise to know whether or not it is 1:12 or 1:9.
Dispite what you read on this site, there are certain mathmaticical and engineering factors that decide what bullet will work with a 1:12 or 1:9 twist. The 1:12 twist will shot bullets up to 63gr.; some barrels will perform better with 55gr, some with 45gr, some with 62gr.. The manufacture of the case, powder, primer, bullet and how you reload or how the manufacture did, makes the differance. The same go's for the 1:9 twist, they will normally handle up to 70gr, but that does not mean that with the right load, it won't shoot a 45gr with a 1/2" group.
1:9 for bullets up to 70gr.
1:12 for bullets up to 63gr.
You make the choice based on science, not bad information!