I can only partly explain the usage. With most conversational topics the adverb usually precedes the verb. This particularly includes advice and instruction.
Lightly fold the flour into the well beaten eggs. Judiciously add
cinnamon and nutmeg. Immediately place in the oven.
(But to emphasise a command the adverb follows)
Call the fire brigade immediately. Walk quietly to the place of
assembly.
A weak or conventional adverb usually sounds fine in a weak position:
The Eurozone is apparently turning into a Superstate.
The Eurozone is
eventually going to come out of this crisis.
A startling adverb sounds better post-positively.
They messed up spectacularly.
They marched relentlessly.
The currency fell dramatically.
They suffered harshly.
But there are many adverbial phrases which are commonly terminally placed as a coda.
The Eurozone is apparently turning into a Superstate even so.
The
Eurozone is eventually going to come out of this crisis in good time.
They messed up spectacularly even so.
They marched relentlessly on and on.
The currency fell dramatically on Friday.
They suffered harshly as well.