I wanted to do what JD did and generally it worked, where the entry has both tags (see entry for 解雇, screenshot attached). I have the old HSK ones tagged OHSK# and the HSK 3.0 tagged HSK#.
However, for a particular word (雇佣), I run into issues. The entry I find when I use the search feature has only the new HSK7-9 tag, but I know this word was also in the old HSK. Sure enough, when I click the same word next to HZ in one of the dictionary entries, it brings me to another, separate entry that has the old HSK tagged on it. Attached screenshots for reference.
Obviously it would be ideal to have these combined. I imagine this is not the only case where this happens, though I don't have other examples right now, only a vague sense when going through some words tagged only with HSK3.0 that some of them might have also been in the old set (I could be totally wrong though). The issue might have something to do with the definition having a traditional variant (which is what I gather HZ signifies?), but ideally since I'm using simplified these entries would be merged.
Not sure if it matters, but I should say that I installed the premade HSK3.0 cards after the recent 3.2.63 update.