hooboy, lots a questions Jeff.
First thing I see that needs clarification is you state that you use 2kw’s a month.
Kilowatts are a unit of power, it is an instantaneous measure. Power expressed over time is watts per hour, or kilowatts per hour (kwh).
I find it very difficult to imagine that you are only using 2kwh’s per month.
A 5 watt device(maybe a small radio) if left on 24 hours a day, for a month would use 3.6kwh’s, nearly twice what possibly your stated usage is.
So, please confirm how much power you use monthly. You need to define that before getting in too deep.
I have built one panel in my life, in college back in 1980. Techniques have improved since then, but unless you are extremely tight on money, or want to say you did it. It is much better to latch on to commercial built units. Homebuilding a panel and making it weather proof to where it will last 30 years will be a major challenge.
I have stuck to commercial panel since. My current system has a power rating of 2.2killowatts of PV. On a good day I have produced close to 12kwh’s, on a bad day, well that is what the batteries are for 
There are poster’s here that can answer some or all of your questions. Just need to take it in small bites.
bob
