u could just use straight up paperclay but as u saw they created a barrier between the apoxy w clay so u should b ok. i personally would do a base of model magic then covered w paper clay then sanded then another light layer of paper clay to give it the smoothness.
Anime and Kpop cosplaying is life~
RapMonster- BTS N.O
fem!Ravi- VIXX Hyde
Hyuk- VIXX Voodoo Doll