Writing here I’ hadn’t seen this post. 
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I understand your desire to save storage space, but consider this:
With a “HiFi compressed” DNG file, you’re currently still dependent on DxO software,
whereas e.g. the (large) TIFF output format is universally compatible.
Instead of limiting yourself now to noise reduction, but retaining other corrections, simply apply PL to your raw files, work with space-saving virtual copies and then export only the currently important images in your desired output format. – That’s the least effort and you still save archival space.
( While I do printing, for which I still use PS with custom layout, etc., I even keep the finished version into which I’ve invested so much work. )