Could you explain what is meant by "cross planes"?
When you connect strings in series across these different "planes", am I correct in thinking that performance of the entire array diminishes to that of the worst performing string? This is what I'm worried about most. I get some really nice sun on the south facing roof at a time when I'm worried significant shadowing will fall on the panels to the east (though I must say that I have yet to go up on the roof late in the day to see what actually happens).
My vendor is fundamentally opposed to micro inverters on the basis of introducing multiple potential sources of failure and his reckoning that in the not too distant future micro-inverters will be built into panels, making separate ones obsolete and difficult to obtain replacements for.