Lots to unpack here!
The orange storage case has some nice benefits. It's sealed, and protects your gear from moisture during transport. It's sturdy, and that's the single best recommendation for its use, especially when airline personnel abuse your bags. That said, it's compact. When I use mine, I disassemble the hoses from the regs, and often don't even put the hoses in the box. What it is, is tremendous protection for your regs. But if you're not comfortable installing and disassembling hoses, then it could get a little cramped. But if you don't want to disassemble, that's fine! You just need to use a creative packing technique like the photo above.
Excursion vs. Signature...
Let's start by saying, IF you can tune your own regs, and IF you have access to parts, you can make almost any cheap reg perform perfectly adequately for the duration of a dive trip. But that's not why you bought Deep6! It will easily last 30 years, and its performance is as good as any reg out there.
Perfectly tuned, and at the same Intermediate Pressure from the first stage, you might be hard pressed to feel a difference above 60' between the Excursion and the Signature. I'm not sure you can even feel a difference on a deep dive with either reg.
But there is a difference between the two. The turret on the Signature first stage increases hose routing options significantly. If you're a single tank recreational diver, that should not matter.
The coatings and components are higher quality with the Signature. That means greater longevity. But if you're just getting started, value may be the more important characteristic, as you look at bcd, wetsuit, dive computer (the other Excursion!!) and extras.
For experienced divers looking for a long-term high-performance reg set suitable for technical diving, the Signature is made to order. Sealed, reliable and easy breathing.
But then, the Excursion is sealed too! Just no turret.
What you'll find is that folks often own both. The heavy case of the Excursion second stage is impervious to abuse by boat crew. It makes a relatively inexpensive backup set for a bucket list dive trip, because even though you have a service kit and can fix your own reg, who wants to do that in a vacation hotel room if you have a problem? Much easier to pull out your well-tuned value set until you get home. Of course, the far more likely occurrence is that your Signature set is working great. Instead, you're loaning your Excursion set to a dive buddy who has problems with his gear.
And if you're just getting started, and are bewildered by all the choices? It's easy. The Excursion set won't set you back an arm and a leg. You'll be good for decades. It's a superb breather. You can service it yourself (with training). And when you're ready for top of the line and need a turret? The Signature is ready and waiting.