The Croatian Velebit is home to a herd of Boskarin cows owned by the Tauros Project. Boskarin are cattle of the Steppe-type, with influence of Podolica, Maremmana and Chianina. They lack, typically for the Steppe-type cattle group, the red pigment in their coat colour, have horns varying in size from medium- to large-sized, are upright and varying curvature (tending to the lyre-shaped type of Gray cattle). The skull seems to be either longish or "normal", but not paedomorphic. I am basing my description of their looks on the photos on the web.
Sayaguesa will add the necessary amount of red (and black) pigment, and also turn the horns forwards. The long snout of Sayaguesa is positive as well of course. Perhaps there will be some nicely aurochs-like individuals in the second generation (first-generation animals might look good too, but these are genetically irrelevant). Second generation means that we will have to wait for about 3 years until they are born (roughly one year until the first generation is born, depending on when the bull first covers the cows), plus another 2 years until - at the earliest - the first young cows are ready to be inseminated by the bulls. Then, another 9 months pregnancy + 2 years at least until you can get an idea how the crossbreeds will work work out. This makes eight years, so we will have to be patient.