Hello!
Thank you for the input and for using openCARP!
Clearly from a performance perspective binary data would be helpfull in your situation. Generally speaking, we try to keep the number of different formats as low as possible, as formats add to the costs on multiple axes (maintainance, documentation, training, ..). Also, binary data has the disadvantage of increasing the difficulty for people to add their own post-processing steps.
I would advise to process the LAT data as a post-processing step in each simulation job. You can interpolate LATs onto your coarser mesh or do at least a conversion to binary. Meshtool can help you with that. See "meshtool interpolate nodedata" and "meshtool collect".
Best wishes,
Aurel