Seasoning aside, the big secrets to making a steak of the sort of thicknesses we're talking about are:
(1) Clean and well lubricated grill with both very hot, and mid-hot zones. (2) An adequate resting period after cooking.
Allow the steak about twenty minutes out of the fridge, season it, and allow it another twenty minutes to come to room temp. Put the steak on the hot part of the grill, and allow the grids to tattoo the steak -- usually around 90 - 120 seconds. Rotate the steak 45* to create a cross-hatch pattern. Note: If you have enough grill space, use a fresh area. Turn the steak over and repeat, as before. Test the steak for done-ness with a finger push.
If it needs further cooking, move the steak to the mid-hot zone and allow it to finish. Experience will teach you how long that's going to take -- divide it in half and try to get equal cooking on both sides.
Remove the steak, put it on something warm -- or at least out of the draft -- and allow an adequate rest period. 5 minutes for a 1" steak is barely adequate, 7 minutes is better. The rest evens out the color distribution and "settles the juices" so they don't run out when the steak is cut and leave it dry.
Sizzle plates are a nice way of bringing some heat back to the steaks for service.
There are several good ways to get extra gloss on steak. Most of them involve butter to one degree or another. The simplest is to brush the steak with melted butter just before service. Another is to put a pat of regular or compound butter on the steak while it's resting -- that way it goes to the table about half melted and half oozing. A pretty sight. I usually make a reduced wine/stock
jus and "butter mount" it, not only because it's enhances the steak but because it unites the garnishes with the steak.
This is dinner for two, ready to plate. It appears that someone ate one of her croutons before I could get dinner on the plates. Note the jus on the plate with the rib steak. Note also, the gloss on the steak.
If you want to talk seasoning we can. But as to how Outback in particular does it, you're on your own. I doubt you'll find their exact ingredients or be able to mimic all of their techniques, but don't doubt you can do better.
BDL