Dear Max/Lieber Malcolm: The Rudolf/Frager Correspondence

Quoted here is one of over 300 letters in the correspondence between Malcolm Frager and Max Rudolf, covering the period from April 1982 to September 1991. This collection reveals the range of musical discourse between two functioning geniuses whose whole lives were devoted to music and musicianship. Of special interest are the comments on the performance of Beethoven's work, interpretation, dynamics, and especially tempi.
Dear Max,
Many thanks for your letter of March 26th. I must tell you that I have turned down an offer to record with Harnoncourt and the Concertgebouw. This was a difficult decision to make, but I feel it was the right one.
I would be delighted to have a copy of the Eingang</ei> for the second movement of KV 415. I am very fond of it.
I do believe that a trio to minuet should be more or less in the same tempo. I wish I could find written verification of this.
What your friend was told about it being customary to make inner repeats in Germany is news to me!
I heard Alfred Brendel when I was in Amsterdam, and he did NOT make the inner repeats in Op. 31/3, even though they are written out.
The enclosed list, which I made up, comparing the tempi for the Beethoven Concerti given by Czerny and Kullak, will not be news to you. But I am interested in Kullak's tempi for the second movements of the 4th and 5th concerti.
Incidentally, I have a question about the quarter note in the 3rd bar of the 2nd movement of the 4th concerto. Most conductors want to hold this note tenuto, forgetting Beethoven's marking of sempre staccato. The staccato dots in the following bars are, I believe, missing in the manuscript copy in Vienna.
My tempi for K. 451 were about as follows:
Allegro assai</ei> q = 160-168
(Andante C) q = 72-76
Allegro di molto h = 76

Many thanks again for your letter and my love to Mrs. Rudolf,
Malcolm