[nq:1]About a year ago, for reasons I won't bore readers with, we came into possession of about 40 books by ... corresponding "-yly" spellings. [/nq] My suspicion is that "dryly" would actually conform more to common practise, because in this - as in spryly and wryly - you have a long and emphasised vowel, with the others you are approaching schwa.
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