destination/maildir: Manuals seem to use different standards / how to configure correctly?

Hello,

I'm trying to setup a dovecot installation with getmail and found these 
instructions:

1. http://pyropus.ca/software/getmail/configuration.html#destination-maildir
    using "~/Maildir/"

2. https://wiki2.dovecot.org/HowTo/TriggerGetmailOnIMAPAccess
    using "~/.maildir"

3. Using Arch Linux, I've set "mail_location = maildir:~/Maildir" in 
"/etc/dovecot/conf.d/10-mail.conf" as advised in their wiki.

As these folder names seem having to do with storage format, I don't 
want just to guess, so which variant would be correct?

Just to make sure, I'm using the correct toolset:

I want to move all my mail documents off of my provider (GMX), and I 
want everything to be stored locally. So I want getmail to fetch 
everything, including folder structure and forder contents (using IMAP). 
Dovecot should be used as my incoming mail server. As I'm usually not 
allowed to relay outgoing mail, I'll need to use my providers server 
directly for outgoing mail:


+---------------------------+ +-------------------+
|                           | |                   |
| Mail client (thunderbird) +-------------------------------->| SMTP 
server (GMX) |
|                           |            |                   |
+---------------------------+                        +-------------------+
              ^
              |
              |
+------------+--------------+       +-----------------+ 
+-------------------+
|                           |       |                 | 
|                   |
|        Dovecot LDA        |<------|     getmail |<------+ SMTP server 
(GMX) |
|                           |       |                 | 
|                   |
+---------------------------+       +-----------------+ 
+-------------------+

Hopefully, also the "Sent" folder will be moved into the maildir and 
seen by dovecot ...

My .getmailrc currently looks like this:

[retriever]
type = SimpleIMAPSSLRetriever
server = imap.gmx.net
username = [email protected]
port = 993
password = top secret ;-)
mailboxes = ALL

[destination]
type = MDA_external
path = /usr/lib/dovecot/deliver
arguments = ("-e",)

[options]
read_all = false
delete = true
received = false
delivered_to = false
message_log = ~/.getmail/mvmail.log

Currently, I don't want to try this yet, as I don't want to loose my 
emails. Is there sth. like a "dry-run" option, i.e. sth. to just copy 
the mails without removing them from the server?

Kind regards

Peter