[Users] how to make ff email wrap at a given length

[David Niklas]

Hello,
I want to make format flowed emails wrap at 80 chars regardless of screen
size.
I have two problems.
1. What option do I set?
2. (harder) What do I do about digests?
For example, this debian digest contains at lest 1 ff message and I'm
uncertain how or if claws mail will be able to distinguish them from a
message that has been purposefully horizontally elongated for the purpose
of preserving the data.

Thanks,
David

Here are the headers from the said debian digest for your viewing
pleasure.

Return-Path: <debian-user-digest-request at lists.debian.org>
Received: from bendel.debian.org ([82.195.75.100]) by mx.mail.com
(mxgmxus005
 [74.208.5.22]) with ESMTPS (Nemesis) id 0LsjwV-1cmgoY20CH-012KWY for
 <doark at mail.com>; Mon, 14 Nov 2016 21:27:59 +0100
Received: by bendel.debian.org (Postfix, from userid 38)
 id CA67321A; Mon, 14 Nov 2016 20:27:57 +0000 (UTC)
From: debian-user-digest-request at lists.debian.org
Subject: debian-user-digest Digest V2016 #1081
X-Loop: debian-user-digest at lists.debian.org
X-Mailing-List: <debian-user-digest at lists.debian.org>
archive/volume2016/1081
List-Id: <debian-user-digest.lists.debian.org>
List-Post: <mailto:debian-user at lists.debian.org>
List-Help:
<mailto:debian-user-digest-request at lists.debian.org?subject=help>
List-Subscribe:
<mailto:debian-user-digest-request at lists.debian.org?subject=subscribe>
List-Unsubscribe:
<mailto:debian-user-digest-request at lists.debian.org?subject=unsubscribe>
Precedence: list
MIME-Version: 1.0
Content-Type: multipart/digest;
boundary="c434756cc1c76e6d998ccea90c4d12c4"
To: debian-user-digest at lists.debian.org
Reply-To: debian-user at lists.debian.org
Message-Id: <20161114202757.CA67321A at bendel.debian.org>
Date: 11/14/2016(Mon) 15:27
Envelope-To: <doark at mail.com>
X-GMX-Antispam: 0 (Mail was not recognized as spam); Detail=V3;
X-GMX-Antivirus: 0 (no virus found)
X-UI-Filterresults:
notjunk:1;V01:K0:QH3MmiapeQE=:+Jne2mZgaNaYgTyxdrGDJKHpQx
<snip>
 Brn5CGGLZlLmTRlnEZh4=

Content-Type: text/plain

debian-user-digest Digest				Volume 2016 :
Issue 1081