If you discharge with 20A average load, the 100AH battery gets discharged in 2 hours (because you don't want to shorten the battery life by discharging it more than 50%). As you'll be discharging anyway, there's no need to limit current from the solar. If, at any point, all loads disconnect, and solar produces 6A, the battery voltage will rise, which will cause the charge controller to lower the current. However, IMHO, putting such high loads on the battery is pure madness.50 Amp is the peak load current and may exist for a short period of time (for 2 to 10 minuets). Average load current is approx 20 +- 5A. It won't drain out as much quickly because solar is providing 6Amp constant charging. So if the load sucks 16Amp, battery discharge rate would be just 10Amp. Won't it?
If you want to charge from AC and draw load from inverter at the same time, it's a huge loss of energy which will dwarf the amount of energy that you get from the panel. The best way is to power some of the loads (looks like you have many) directly from AC, and to put other loads on the battery. Because of huge losses, AC charger should be used unly in emergency, e.g. when batteries are discharged and there's no sun to charge them back.
To keep the 100AH battery properly charged with solar, you'll need to double your panels to provide about 12A. This will produce enough energy to feed 2-3A average load.