You want more Watts. And more Amps.
Most panels put out 15v so charging can ocurr.
The more panels the better.

What cells are yout going to use. Poly silicon?

Actually the typical panel is wired with 36 cells to give you a voltage of about 18 volts when measured open circuit. The voltages drops when you put the cells under load. Check out a V-I plot and you will see what I mean. That is why you go for at least 18 volts so that under load you can still charge. Don't forget you will also have a voltage drop through your charge controller. Panels are really rated for full sun. If you have cloudy conditions you probably won't have enough voltage to charge. Also from the V-I curve you can see that there is a 'knee' where if you draw too many amps you get zero volts very fast. That is why they build those more expensive MPPT charge controllers.

With solar panels,you don't set the voltage to anything. Your regulator looks after all this.

Old regulators threw away the excess voltage when the sun was shining and didn't work when it was too low. New regulators convert too high/too low voltage to just right voltage.

As to batteries,the practical advice is to have the fewest parallel strings, because a faulty one drags everything else down to its level, aka can drain everything else. One is idea, but no backup, so my 2c is the duplicate everything, so if one fails, the other is still working whle you repair the other.

Parallel/serial is really irrelevant. How much capacity do you need? Volt voltage is your battery bank going to be? What voltages are your inverters and/or devices?

You buy DEEP DISCHARGE batteries and deep-discharge batteries only. Marine batteries are not deep discharge. Over hear, if it has a CCA battery, then it is a car starter battery. what you want is the AmpHr rating.

I buy Trojan Brand.

Capacity determines what you get. i would suggest buying a 12V trojan deep discharge of the biggest capacity that you can move. That is the real gotcha, how are you going to move it about, to position it, to connect it, to remove if for testing, for repair, etc, etc.

12V 100AmpHour are fairly common, so it might be a good idea to get one and a panel or two and a regulator and play around and learn. Hint, get a battery meter and take voltages all the time. It helps work out an approximate idea of what state your battery is in. Find and read the Bill Harden/WArden Lead Acid battery FAQ on the net.

A good panel, some sun, etc, should allow you to run a 20watt light, radio and smalllish fan each day.

If you read the FAQ, it will explain how that 100AmpHour battery only is 50Amphour capacity.

Learn about panel postitioning, decide on tracking, yes or not,

If you wanted 200Amphour capacity, then look at 2 x 6V 200Amphour batteries, or even 6x2V 200aphour batteries. That 12V 100aphour weighs ta bout 35Kg (77?lbs).

Happy reading.