With a 600 ah bank to be charged and maintained, the easy answer is as much as you can. Drain that bank down to 50% and you will need to replace 300 ah is a relative short time plus cover your daily loads. A single 24v panel and Mppt controller will put out less than 20a is the best conditions, so you would need at least 15-20 hrs to bring the bank back up if you were not using it.
In reality you need to figure out roughly how much power you use daily. What kind of conditions you camp in. What kind of loads are you running and how often do you dry camp. You already know the size of your bank and there is a recommended amount of solar needed to take care of it.
