Ok. Sorted!
Thanks to this post I could figure out my solution I'll post here: https://mugenguild.com/forum/topics/special-screen-1-0-zoomout-stages-188452.msg2460659.html#msg2460659
Add those vars / fvars into the root state:
[State 20000, Increase Size]
type = VarAdd
trigger1 = 1
v = 0
value = 3+(var(0)=-3)
[State 20000, Angle Control]
type = VarSet
trigger1 = var(0)<=160
fv = 1
value = fvar(1)-ifelse(var(0)<=10,25.0/(var(0)+20.0),0.02)
[State 20000, Image X Scale]
type = VarSet
trigger1 = var(0)<=10
fv = 10
value = ifelse(var(0)<0,1.0/var(0),var(0))
[State 20000, Image Y Scale]
type = VarSet
trigger1 = var(0)<10
fv = 11
value = ifelse(var(0)<0,var(0),1.0/var(0))
[State 20000, Image Y Scale]
type = VarSet
trigger1 = var(0)=[10,160]
fv = 11
value = (1.0/10.0)-log(0.82,var(0)-9)
[State 20000, Image Y Scale]
type = VarSet
trigger1 = var(0)>=160
fv = 11
value = 0.001+fvar(11)/2.0
I deleted the Helper and added this Explod instead:
[State 20001, Self]
type = Explod
trigger1 = Time = [252, 452] ;1
anim = 3211
ID = 1
space = screen
pos = ifelse(facing,(screenWidth*0.5-170),(screenWidth*0.5+170)), (20+0.5*fvar(11))
scale = 0.23,0.23
;angle = (parent,fvar(1))*(0.01+1.7/(time*0.23+1))*facing
facing = 1
removetime = 1
pausemovetime = 9999
supermovetime = 9999
sprpriority = -10
ownpal = 0
PS: I commented( ; ) the "angle" because it is a plus feature to give us an "anim effect" with the fvar(1) code help. Without it there is no anim.