Name and register
In the official list Solanotto stands as a single name with no alternatives attached to it. That is worth noting, because not every mention around it is so straightforward. Altenasso is registered as "Altenasso (o Garblet Suè o Garbelletto Superiore)", which means Garblet Suè and Garbelletto Superiore are alternative names for that one site rather than separate vineyards. Vignolo is a third mention, registered separately and under its own name alone.
The boundaries are a different matter. The detailed cartography of the Barolo mentions, for which the reference work is Alessandro Masnaghetti's, is not openly published, and Solanotto's perimeter and the list of mentions it actually touches cannot be established from freely available sources. Published claims about which crus Solanotto borders, as opposed to which crus lie near it or face it across a slope, should be treated as unconfirmed until checked against that cartography. Adjacency read off a polygon map is not the same thing as a border as the literature describes it.
For the same reason, no figure is given here for the site's extent, mean elevation, gradient or exposure. None of those could be sourced.
Producers
Solanotto is a name that is hard to find on a label, and the two estates most often associated with it do not, in their own published material, connect a wine to it.
Azelia, in Castiglione Falletto, builds its Barolo Classico from seven crus, 30 percent of the fruit from Castiglione Falletto and 70 percent from Serralunga d'Alba, from vines averaging fifty years on a white calcareous soil tending to clay, between 250 and 370 metres. The estate does not name the seven sites, and Solanotto does not appear among the vineyards it identifies. That declared altitude band is an estate-wide range covering seven parcels in two communes, so it carries no information about the elevation of any single one of them and cannot be used to place Solanotto on the slope.
Cavalier Bartolomeo was founded in 1924 in the hamlet of Garbelletto, below Castiglione Falletto, and makes around 15,000 bottles a year in total. Its range is a Barolo Altenasso, a Barolo San Lorenzo, a Barbera d'Alba and a Grappa di Barolo. Solanotto is not among the vineyard names the estate uses, and no Dolcetto d'Alba appears in the range.
What can be said, then, is narrow. Solanotto is a delimited mention of Castiglione Falletto that seldom reaches a label under its own name. Whether it functions primarily as blending fruit inside commune-level Barolo is plausible but undocumented: no producer's own published material sets out a blend that includes it.