Lots of good advice here and some that is a bit unusual...... Between your two I would do the .270 because it will prove to be more versatile. From 110 grain to 160 grain bullets, if you handload. Mostly in factory ammo the choices you will find are 130 grain and 150 grain. I notice you are in South Africa, I don't think your Dad will be able to have multiple rifles in the same caliber so matching his may be out of the question. Where it me, and I know this wasn't on your list I would do the 30/06. Much wider selection of bullet weights up to 220 grain ( thinking up to Eland and Giraffe ) down to 150 grain are pretty common over there. If you do get into reloading it is a very common and versatile round and components and tools are readily available. I am almost certain that the rifle model you mentioned is available in this caliber. Very hard to beat the old '06. The .270 WSM is a gonner, it is not gonna be around for too much longer and ammo or brass for handloading is gonna get tough to find and expensive, I would avoid that one. Whatever you decide best of luck and good shooting.