The perfect set of settings are the settings they use in the lab to get their life cycle numbers. They include temperature, charge rate, voltage settings for both bulk/absorption, float settings, time in the absorption phase. Our vans will never be able to match the environment of a lab. We can only try to get as close to as we can.
Temperature is the first one that we can only minimize. This is one of the reasons for the recommendations for moving the battery inside. while everybody worries about the cold temp charging issues, high temps will negatively effect those numbers also.
Charge rate sounds like a simple one, but really we are limited by the chargers capability and the size of the battery bank. The larger the bank, the more charge capability we actually need. So we may just run out of the top end the charger is capable of. Some chargers are limited to one output, such as most DC to DC chargers. Solar you can be limited to the amount of sun. Charge rates are higher for lithium versus lead acid
Voltage setpoints, this is one of the more important ones. Generally they give you an acceptable range, but also will usually give you a specific target voltage. The acceptable range generally now matches what the range of lead acid batteries. I suspect that this range is derived more on not making you upgrade equipment (making the sale easier). If you can match their specific target certainly it would be better to do so.
Float voltage is another one that generally the have a range for, specifically below a certain voltage. In the early days, most lithium chargers did not have a float stage. They were a two stage charger. Now almost all the battery vendors are comfortable with a float voltage as long as it low enough.
Absorption time, many chargers don't give you the ability to set absorption time directly. If you can, take advantage of it. Your charger also may have the ability to increase absorption time with a deeper discharge, this is also not needed for lithium.
Equalize is another stage that is not needed for lithium. Actually is wasn't generally an acceptable setting for most AGM batteries. If your charger has an automatic equalize setting that can not be turned off, you should set the voltage to the same bulk/absorption setting. This is one where I might draw the line, and go with a new charger if I couldn't disable automatic equalization
Another setting could be the voltage that it will start the cycle again, if using a two stage charge this will be how far the voltage can drop before they try to top it off again. This setting is generally more relevant on shore chargers.
To be fair lead acid batteries also had many of the same issues, so this really isn't new. Many times your bulk/absorption and float levels were at the mercy of what the charger had. They didn't always match your manufacturers battery specs.
One area that Lithium can very greatly from lead acid is long term storage. Generally lead acid we get it full charge and disconnect. Check with your lithium vendor, because many do not want you to leave it at 100% for long term storage.
So we try to get as close as we can, the advantages of lithium are real. The fact that they don't need to be fully charged each cycle is a game changer in our environment.