Hi, Chris,
Just wanted to let you know that there is code at GitHub that will allow converting a .tdms file into .mat file. This m script will operate on large file fairly quickly.
This is a much faster way of getting the data between DIAdem and Matlab. Hopefully the format in workspace works for you.
If this is of interest, and you have trouble finding the m scripts. Let me know, and I will forward the link.
Paul