In reality, unlike Hollywood, both the M9A1 HEAT rifle grenade and the 2.75" bazooka round penetrated about 100mm of armor. The only difference was the bazooka round could be fired to a theoretical maximum range of about 600 yards while the rifle grenade would only make about 100 yards. I doubt you could hit much of anything at more than 100 yards with either weapon so the difference is negiable.
As the side and rear armor of a Tiger II is in most places about 80mm it is possible to knock one out with either weapon but it is unlikely. First, the actual penetration is likely to vary from the theoretical and not in a positive way. Second, even if a penetration is made the effect is likely to be small as there will be little residual blast effect.
I would say that on a Tiger II the most vulnerable spots were just behind the turret on the hull, particularly between the tracks and the upper hull and the rear of the turret. The first location would strike a fuel tank and possibly set the tank on fire. The second location is into an unprotected ammunition rack and likely to set off the ammunition resulting in the destruction of the vehicle.
From the front the Tiger is invulnerable to either weapon although it might be possible to get a penetration if the hull machinegun ball is hit. Other than that aiming for and striking the gun barrel might be effective or aiming for the commander's cupola could work. Also at least with the rifle grenade it might be possible with a skilled firer to lob a rifle grenade such that it struck the top of the vehicle rather than the side. But, of course, all of these rely on a large degree of luck to work.