mahlerite54,
Welcome to the Mahler Board!
Klemperer's typical set-up for his Mahler recordings with the Philharmonia Orchestra was:
1) First violins far left
2) Second violins far right
3) Violas center right
4) Cellos center left
5) Basses left, behind the cellos and first violins
I just spot-checked the recording you mention with score in hand, and these placements are pretty much what I hear. The very beginning is a bit confusing, however, as the second violins and violas way overbalance the firsts, making it sound as if most of the high strings are on the right. Balance improves as the symphony progresses.
James