Good work , and I hope you will "bulk" up the arm ... When I´m greenstuffing I try to plan ahead and let it dry in between . So I suggest that U start with some lesser daemons too so U have somewhere to put the leftover greenstuf . And also try with some wire instead of sprues , it´s easier to get to the shape that U want instead of the shape of the sprue .
Try some other horn´s , It looks like an evil Leia

( joke , if U are sensetive )
Unskul ...