If you are creating a composite of high-resolution images, you can enable proxy processing options. In this case, you work with proxies to create your composite, thereby demanding less of Backdraft Conform in terms of memory management and intermediate processing (such as previewing results in-progress). You can also process proxies for soft effects on the timeline.
When you are satisfied with your result, switch to full-resolution processing, fine-tune settings to account for changes introduced by the higher resolution clips, and then process the result. This workflow can greatly accelerate your work.