Two panels on a railing is a different question from a roof. The angle is whatever the space allows, the inverter is capped, and a small home can only swallow so much at noon. This runs the same money engine as the rooftop calculator on top of a production model built for a panel that might be standing straight up.
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Nothing you send to the grid earns anything here. Plug-in kits mostly can't export, and at this size there'd be little to sell anyway. What the home can't use at noon is simply thrown away, which is why the usable share matters more than the nameplate.
Legality isn't modelled, anywhere. Rules for plug-in solar are changing fast and differ by state and utility. This calculator doesn't tell you what's permitted where you live. Ask your utility before you buy.
The angle model is measured. Every market on the list was run through NLR's PVWatts v8 at eight tilts and eight facings, 896 runs in all, and the calculator reads between those points. Upright matters more than latitude suggests: a vertical south panel makes 0.52 of a 20° roof in Miami and 0.72 in Boston, because it lives on low winter sun and on light thrown up off the ground. Reading between the measured angles costs 1–2% at the angles balconies use.
Shade is counted in hours, not mapped. The hours you give are taken as the panel's best ones, around the middle of its day. Outside them it still sees open sky, worth about a quarter of direct sun. A railing that gets only early-morning sun will do worse than this says.
Not modelled: a real shade study, wind loading, how you fasten it, whether your circuit can take it, battery storage, or any tax credit. Enter a price you'd actually pay.