If you copy a spell using something such as
Nivix Guildmage 
to copy a spell, lets say
Teleportal 
would you have to pay the Overload cost again for
Teleportal ???
So you pay the
: for the
Teleportal overload cost, giving all of your creatures the effect. Then pay the
of
Nivix Guildmage to copy
Teleportal ... do you have to pay the
again for the overload cost or will the overload cost count as the copy?
Or a more practical example to copy a spell like
Dynacharge 
for it's overload cost of
. Do you have to pay the overload cost again so your creatures can get +4/+0?
Or another example if your opponent uses an Overload ability and you activate something like
Reverberate 
to copy it, will you only get the initial effect and so have to also pay the overload price or will you get the full effect of the overload of the copied spell??
