The results are meaningless without the correction file. The calibrate SPL has nothing to do with correction except to balance levels between the real meter and the REW meter.Any thoughts on whether I should load the correction file, or is it enough simply to calibrate the SPL in REW?
Load the correction file and apply the changes to the mdat files. Use the Impulse Response Windows 'Apply Windows' button after loading.
You will then need to redo all your filters.