LumenRT for large Datasets

I have 30,000 reference files, coming from 3.5 Gbytes of i-model data. I need to get that into LumenRT. I have tried building up the scene files gradually, turning on references and exporting to LumenRT step at a time. I got a quarter of the data in before it started crashing LumenRT.

Are there any suggestions for getting large datasets into LumenRT.