One of the things that needs to be considered is FOC. You want to try to keep your FOC somewhere between 7 - 11% however this is not a hard fast rule, it is whatever flys well for your setup. Increasing tip weight will increase FOC.

Another thing to consider is arrow spine. With your draw length and weight, if you are sitting right on the border between two different shaft spines increasing your tip weight will have the effect of reducing the arrow spine a bit and may push you toward the stiffer of the two shafts.

As far as changes in KE with tip weight, I think you will find that the KE is essentially going to be nearly equal for all arrow weights (possibly just a bit higher for the heavier arrows). What will change is the speed. As your reduce the arrow weight, the speed will increase but KE will be essentially the same.

KE = (arrow weight / 450240) x (velocity x velocity)

The other factor that accompanies the speed change is arrow drop. Obviously a faster arrow will have less drop over the same distance....this is why the 3D shooters are looking for these lightning fast bows with ultra light arrows. An error in yardage estimation does not become such a problem with a flat shooting arrow.

For hunting my personal preference is more in the middle of your arrow weight range. 8.4 to about 9.5 grains per inch shooting a 100 grain tip is what I use.
This gives me a good compromise of speed, arrow weight, drop and downrange energy.

Essentially it comes down to YOUR preference and what shoots well for you.
Some other good brands to look at are:
Gold Tip: Very economical to shoot and stand up very well
Beman: ICS Hunters and ICS Camo Hunters

I have heard that the Vapor arrows fly pretty well but their durability is not that great. No experience with them, only what I have heard.