Assuming you log in with the same Apple ID on your new Mac as you do on your iPhone, it doesn't really matter which way the apps sync. Both devices will have access to those same apps because you don't have to pay to re-download apps you've already bought under your Apple ID.
Now, as far as app data is concerned, like your savegames, those don't sync anyway. If you back up your iPhone to a computer, that backup will have your savegames (when you restore from backup, all-or-nothing), but if you delete an app off the phone then use the computer to sync it back, it's going to be fresh; no savegames, same as re-downloading it.
You can get your iPhone now. When you first sync it later, it's not going to delete anything from your phone. Although, my experience is based on having everything set to manually managed. I'm not positive what happens when you have auto-sync turned on for stuff. But this concern would only be for app data like savegames; the apps themselves are already bought and can always be re-downloaded for free.