Try the sound of the trill begining with F ....Claudio Arrau editions sugests that way.
Try the sound begining withy E...as Jenner, Schenker and Bullow sugest at respective editions.
In Henle editions no sugestions.
I prefer to attack ALMOST as a chord C E F, almost simultaneously..and not CE or CF....
Could be a bad and wrong advice, BUT, It sounds better for me... at high speed this sugestion could be very useful....as a chord, we don't know if begins with the principal/real note or if begins with auxiliary/superior note...it's very useful only in fast tempo.
In a good piano with fast repetition this "trick" perhaps be unnecessary.
Remember, a chord is the fastest way to play melodic notes.....so...think about... and try almost as a chord at high speed.
By the way, Bullow says..."As an exception to the rule, this trill must not begin on the auxiliary, so as not to blur the melodic outlines; seven notes 3 5 3 5323 2 vigorously played suffice in such rapid tempo."
Pedro