Qualification for Raganuga Bhakti

Sri Jiva Goswami's Bhakti-sandarbha 311

ajata-tadrsa-rucina tu sad-visesa adaramatradrta raganugapi
vaidhi-samvalitaivanus heya/ tatha loka-sangrahartam pratis hitena
jata-tadrsa-rucina ca/ atra misratve ca tyatha-yogyam
raganugayaikikrtyaiva vaidhi kartavya.

One in whom this taste (ruci) has not arisen but who has come to
appreciate raganuga-bhakti only on account of appreciation for a particular
saint or scripture (sat), may still practice raganuga-bhakti but with an
admixture of vaidhi-bhakti."

In the same way, for the sake of preaching (loka-sangrahartaham) one who is
advanced and in whom taste has manifested should also practice raganuga with an
admixture of vaidhi.
Such mixing of the two kinds of bhakti means that one practices vaidhi-bhakti
by uniting it with whatever raganuga practices one is capable of."