I don't know enough about the ability of the barrel on the Striker to handle a wide range of bullet weights. If the Striker can handle a fairly wide range of .284 bullet weights and stabilize them satisfactorily then I'd recommend going with the 7mm/08 and getting into handloading. It would give you a great deal of versatility. Kinda spliting the difference between the .243 and the .308!
Actually, really splitting the difference would be a diameter of .2755 .....so why not look into the .270?? Its a .277
I know it doesn't have quite as many bullets available for it,....but again....I don't know how much lee-way the Striker barrels give you on stabilizing different bullet weights. Maybe some of the hand-cannon aficianados here will steer you in the right direction.