I think I've seen this cross in flower in person just once. Looks like you have a very nice one. Do you know the origin of this plant? Original 1908 grex? or more recent re-make?
The plant probably dates back to 1932 at most.
I'm almost done gathering delenatii hybrids of that time. Next are insigne and maudiae then self and sibs!
Actually, if you look carefully, Rossetti and Rossettii are listed as 'this is a synonym', as on the page in your link. Rosettii is listed as 'this is not a synonym' - the original.