ok, first things first.
1)I'd put RF_EXTERNALMODEL in Init function, no need to define it every time imo
2) my code makevectors([-self.v_angle_x*0.2, 0, 0]); from fteskel works only with skel_mul_bone(s) after it
Did you try my fteskel code? If you try it, you'll see that spine is bending with neck and head, proportionally of 20% respect v_angle (that's why that *0.2)
3) How did you export your iqm model? Blender - iqm exporter? ? Because, without that modification, bone order is scattered during exporting and fte can't handle the correct hierarchy so, bending the for example bone#20 is not neck and #21 is not head.
4) I also used csqc-only models. Not deltalisten stuff, I don't trust in deltalisten.
5)Make sure if you export correctly v_angle (make a test print) in csqc
6)Take a look at , just in case
Hope it helps,
cheers