Instead of guessing about the F269U specification, it seems more promising to consider what would be a useful specification to achieve the intended 35V/10A.
It's has been already stated that the SCR preregulator can only reduce the input voltage, not boost it. The text describes the preregulator operation principle, maintaining 4 V accross the linear regulator. Considering the inductor averaging effect (I read it as 1 mH), the transformer must have at least 2x35 V, better 2x38V output. According to double wave rectifier form factor, you need about 10 Arms of each winding to provide 10 A DC, resulting in a 700 - 800 VA transformer rating.