Bear with me if this post is a bit lengthy and not immediately helpful in terms of recipe design, but Augustiner Hell is a matter very close to my heart, and even closer to my liver. In terms of total consumption, it has to take rank #3 among all beverages, behind water and coffee. This post mostly contains general mumblings and unsubstantiated reflections on this iconic brew. Almost all of it is opinionated. Towards the end, you will find some stuff that might be more relevant for replication.
The Augustiner brewery has never run a single ad, yet every teenager growing up in Munich learns from older friends that Augustiner is the only good Helles, while the preferences for Weißbier vary (Augustiner also makes a delightful Weißbier, but its status is nowhere near that of Augustiner Hell). For the sake of accuracy, I should add that Tegernseer Spezial has attracted quite a few followers over the recent years as well, but I will just brush over that fact for now.
Outside of pubs, it is mostly drank straight from the bottle: during the summer months on the riverbed of the Isar, and at home parties throughout the year. Just now: party on new years eve? Augustiner. Hanging out after helping a friend move? Augustiner.
In my opinion, drinking it straight from the bottle is not really the spark of joy it ought to be. The carbonation level is rather high (I am also quite sensitive to carbonation, so others might feel differently) and all you get from each sip is a strange combination of cellar, sugar and a slight bitterness. It seems not to bother a lot of people, but I grab a mug whenever I can. To get rid of some of the carbonation, I pour rather aggressively, wait for the foam to settle, then pour the rest later. Observing this routine, people tend to assume I have no idea what I'm doing and that I am just now pouring my first pint ever. But eh, it's a nice change from being considered a beer snob, so I'll take it. Also, when served on tap, you will invariably find that the carbonation is indeed very low, to the point that you will rather quickly find it stale if you're not drinking quickly enough. The brewery is known to be very thorough in managing all affiliated pubs and dialing everything in to offer a consistent experience across town. I am convinced that this low carbonation level is not a coincidence.
So my advice for anyone trying to replicate this beer is:
shoot for a slightly lower carbonation level. It helps bring out the softness. The sharpness of CO2 can easily cut through the subtle flavours.
Now to the recipe at hand: the OG seems a tad high. Augustiner is brewed at 11.5 Plato or 1.046. I wouldn't go above 1.048. The yeast should be suitable, but I've never used it myself (only got a fridge a couple brews back, just getting into doing lagers). "The internet" attributes WLP 860 (and the equivalent Imperial L17 Harvest) to Augustiner, so that might be worth a shot as well (regardless of its true origin, it seems to be a good yeast). Using some Munich and Melanoidin malt to make up for the decoction should work, but - judging from the pictures in this thread, and lighting might be an issue here - the beer might come out a bit too dark. The IBUs and 60 minute noble hop addition seems just right. It's always tempting to throw in some hops later for added hoppy goodness, but while that will certainly also yield a tasty brew, the homebrewer eager to replicate Augustiner should imo shy away from significant additions towards the end of the boil. Certainly, all hops should be added with at least 15 minutes left in the boil. When fresh (and not drank from the bottle!), Augustiner Hell does seem to have a very slight floral note, so I wouldn't dismiss the idea of a 15 minute addition altogether. The Carapils should not have a great impact on the taste, but I've been really pleased with its impact on foam stability, so I'd keep that.
Don't try and replicate Munich water. It sucks. There's a reason beers in Munich were dark until 1896. Use soft water, as you would with any light colored delicate beer. I should also add that the municipal water in Munich is not actually Munich's "own" water. All major breweries in Munich - including Augustiner - have their own well where they get "real Munich water". So, in particular, do not follow the water reports of the city of Munich: it's not the base water the breweries use, and I am certain that they treat their water.
Another factor whose impact might be hard to judge is the fact that Augustiner also produces malt, a "Tennenmalz" where the the germinating grain is spread over a large surface. Afaik, the actual percentage of this "Tennenmalz" is unknown. A while back, they were about to shut down the malthouse (apologies if that expression is incorrect) because of the cost of space etc., but decided against it after performing a test run (at least that's what they claim, maybe there have been other factors). So using some 15-20% of floor malted pilsner (or some other more characterful pilsner malt) might be a good idea; I'd probably throw out the Munich then.
Ok, this concludes my contribution to this thread for now. I hope it can be helpful to some of you - I've probably had more Augustiner Hell than all other posters in this thread combined

. I've never tried to make a Helles myself - homebrewing has been sort of an escape from Helles, actually - but I might try and make one for a friend's birthday party in March. Take it all with a grain of barley