The 7-08 is a lightish weight rifle. Model 7 with a 24" aftermarket barrel. Next step will be fluting and getting a synthetic stock for it.
The cartridges listed are just the ones I've been offered that intrigue me either due to rifle, perhaps a 760 series in a .35 Whelan or Marlin in a .444 or .45-70 is an avenue I should look at.
Of the ones you mention in your original post unless you handload the 264 Win Mag (which I have and like) isn't a good option so I would go with the 7mm Rem Mag instead since you can get cheap shells at Canadian Tire. The 300 will only add recoil to the equation.
Since you have a 7mm-08 and 30-06 I would look at a 223 instead or one of the ones you just mentioned, the 7600 35 Whelen or a Marlin. The Marlin lever guns have pretty heavy recoil so if the stock doesn't fit well (like it does with me) it isn't fun to shoot.
