I have a very similar setup. I went with the Lensun hood solar panel, GoPower dual bank controller (Aux 1st, Starting 2nd), Redarc dc-dc charger (with solar, just in case, but not used), and a Power Bastards ** alternator (based on your other thread). I'm also pretty happy with the setup. Oh and my aux battery is an Optima blue top.
Yep. My solar panel is the Lensun as well. That feeds to a Victron 15 amp charge controller that is tied directly to the aux battery. The Victron is handy because it has blue-tooth built in which allows me to keep an eye on the amperage output of the solar panel to the aux battery and it's charge level.
My two batteries are separated by a Traxide isolator. It can operate either automatically or via switch in the cab. When the isolator is closed the solar panel serves to charge both batteries, when it is open, the solar charges the aux battery only. With the exception of the winch, all accessories are wired to this aux battery (radios, fridge, lights, spare 12v outlets, on board air, etc., etc.). There is also a voltage cutout built into the Traxide system that will automatically disconnect the starting and aux batteries if voltage falls below a certain threshold.
The starting battery, obviously, is tied to the alternator. Once the alternator spins up, the Traxide supplies charging current to both batteries. I also have a NOCO charger mounted under the hood tied to the starting battery. When the Traxide isolator is closed, this will serve to keep both batteries topped up and is useful for camping when shore power is available or when wanting to maintain the batteries at home.
Finally, I also have an additional solar panel I have prewired in parallel to the permanent panel on the hood that I can throw out when camping to increase the charging capacity to the aux battery.
The short synopsis of this wall of text is that I am as happy as I have ever been with the electrical system on my truck.