I think the issue here is the 0px space between the quotes and sidebearings that occurs at sizes up to 19ppem. Adding a link to the appropriate sidebearing with a 1px minimum distance ought to provide adequate clearance at small sizes without having much affect on larger sizes. However, since the double-quote glyphs are actually composites of the single-quote glyphs, the relative position of each component within the larger width is not instructed (example: at 15ppem the left double-quote overshoots the right sidebearing while the single quote does not). So the double quote glyphs would either need to be delta hinted at small sizes or decomposed and hinted separately.
I think the issue here is the 0px space between the quotes and sidebearings that occurs at sizes up to 19ppem. Adding a link to the appropriate sidebearing with a 1px minimum distance ought to provide adequate clearance at small sizes without having much affect on larger sizes. However, since the double-quote glyphs are actually composites of the single-quote glyphs, the relative position of each component within the larger width is not instructed (example: at 15ppem the left double-quote overshoots the right sidebearing while the single quote does not). So the double quote glyphs would either need to be delta hinted at small sizes or decomposed and hinted separately.