I haven't seen an answer so I will jump in.
Digital phasing has the advantage that the phase shift is independent of hardware and perfectly linear across the MW band, Slight changes to ferrite permeability are not a problem when you do the phase shift with a simple transform.
Recording 2 channels and phasing them post facto really doesn't require a different wav file for each channel. It does require that the PC software be able to locate the samples in each file that were sampled at the same time..
As far as your problems with finding time to play back files, I'll pass on that and view it as a generic problem that is not caused by phasing.
Chuck
http://www.hard-core-dx.com/article.php?story=20190117061504959