Reasons Not To Max Out Roofspace.
Here is the way that I've come up with that may help.
First of all, panels all have dimensions. Also, panels require mounting systems. Ultimately, the space on your roof has to facilitate the rails.
Get yourself nice and comfortable along the ridge of the roof and run your tape measure down to the gutter. Don't measure exactly from the very top to the very bottom! In fact, if your roof overhangs beyond the structure of the house at the bottom, don't consider mounting onto that part.
Here is a way more practical approach. There are only 6 fewer panels in this example (the one above is the 'maxed out' version). But in this version, first of all the array will definitely fit on your roof. And secondly, 32 panels will fit onto a single inverter as 4 strings of 8, which is great!
What would the purpose of those additional 6 panels actually equate to? In all honesty, nothing but a bunch of issues. First of all, 38 panels would require you to break your array into 2 separate inverters, because 38 is not divisible by a number of panels that will series into a string that is compatible with an inverter. You'd end up with 2 strings of 10 and 2 strings of 9, probably, each on 4000w inverters. Now you have twice as many inverters, and only 6 more panels.
I guess that's ok, there's nothing exactly wrong with 2 inverters. But additional costs are not just that you're buying twice as many inverters (rather than a single 7kw inverter). You also need an additional subpanel. It might require a service upgrade. Those 6 panels, at STC 1.2kw, are really going to only generate 900w at max power, 1.4 mW a year in an area like Connecticut.
Hmm, that's starting to sound good again. I guess these are the questions we're forced to ask ourselves before we enter a situation like getting a PV installation though... right?