Although "35" is not noted in the reference to "Alberg" in the drawing, I'm pretty sure that Pearson only produced the 35. I believe the 30 was produced by Whitby Boatworks in Ontario.

But, more important is the difference in the angle of the machined surface of the shoe into which the rudder shaft is inserted. For the Ariel and Vanguard, it is 40 degrees. For the Alberg, it is 35 degrees. Consequently, a shoe produced for an Ariel would NOT be proper for an Alberg -- of course, one possibly could machine the surface angle to 35 degrees without messing up the shoe fit.