I found most panels we see at 11 to 12 % panel efficiency. I found one maker, Sanyo making HIT-220 (even larger in Europe) with panel efficiency of 18%. That gives a 220 watt rating to a panel 31 x 61 inches. Three just arrived today. I also bought Morningstar Tristar MPPT
45 amp charge controller rated very good in user friendliness (programming) and one of the lowest in parasitic losses. Morningstar Corporation » TriStar MPPT
I had originally settled on Blue Sky but was a bit put-off by the complexity of the instructions. For my unit, I would need to set up pots with a VTVM meter. Yuck. In the end, the Morningstar was less than the Blue Sky - simple choice.
We will also add two battery
monitors TM2025RV from Bogart Engineering, one for each bank.
Good advice I noticed above regarding LARGE conductors. Whatever they say, go way up. I followed this long and tedious series of postings (hours) but found a few gems I could use. https://handybobsolar.wordpress.com/
Probably #6 or larger wire is a cheap performance enhancer for most systems.