There’s little to gain from reducing absorb time. I never go below 2-1/2 hours and I’m at 3-1/2 hours now, I’ll reduce it soon as hot weather approaches.

So you have a 24v 400ah battery bank. Mines 470ah at 12v and I use a single Outback fx60 which is more than enough for my 2kw Solar array. Twin 80a controllers seems like overkill.

I highly recommend this hydrometer, it’s about $35, is temperature compensated and makes checking SG easy as pie.

https://smile.amazon.com/MNHYDROMETER-Hydro-Volt-Temperature-Compensated-Hydrometer/dp/B007CW8Y9S

As good as that is it’s annoying to do frequently. It’s best to monitor the charge state with an amp/hour meter that you can glance at. The cheapest one is this one for like $16, I use one on the trolling motor battery in my boat and it’s a little inaccurate but still very useful. It even comes with a 100 amp shunt.

https://smile.amazon.com/bayite-6-5-100V-Display-Multimeter-Voltmeter/dp/B013PKYILS

A much better one is this which I have in my cabin, it’s rock solid and easy to read from across the room. It’s expensive, does not come with the required shunt or wiring (which I made myself, it’s 4-wires and not proprietary).

https://smile.amazon.com/Bogart-Engineering-TM-2030RV-F-TRIMETRIC-Battery/dp/B07537GGKD

The shunt I use is this.

https://smile.amazon.com/AMMETER-SHUNT-500-AMP-MILLIVOLT/dp/B005BHPG6K

You might find them cheaper on Arizona wind and solar