The Aplanat and the Rapid Rectilinear were developed independently, and a court case determined that the appearance of the two virtually identical designs, only a few weeks apart, in two different countries (Germany and England, respectively) was happenstance, not industrial espionage. Believe that if you will. Some swear that the Aplanat was a better lens, the Rapid Rectilinear became more common in America for obvious reasons. It was the go-to lens for most consumer cameras in the last years of the 19th and the beginning of the 20th century, even after anastigmats became widely available. Most models available on the used market are symmetrical, and over here it is a very common lens. It appears on most drop-front, self-casing cameras I see and lots of folders. The older models are in shutters that are marked in the US numbers of 4, 8, 16, 32, 64 (fstops 8, 11, 16, 22, 32). They can be very nice lenses if in good condition, and the Unicum shutters where you often find them mounted are quite often functional, if not anywhere near accurate to time.
I can send you one, Umut, if your painting doesn't work out. The enlarging mirror (convex), by the way is a very good way to project an image onto a white surface, providing you are in a darkened area and your subject is in very strong light. It's been used since the 15th century.