Q:

How do I get the structural images BKChem produces to satisfy these conditions on Wikipedia?

I'd like to know how to get BKChem to create structural images that satisfy these conditions. 

A:

The instructions on the page seem fairly simple (make a couple of files that hold the contents as specified). But if you want to reduce that to a few commands you can just fire off without thinking, this is what they're after:
mkdir ~/.bkchem

cat << EOF > ~/.bkchem/standard.cdml
<?xml version="1.0" ?><cdml version="0.15" xmlns="http://www.freesoftware.fsf.org/bkchem/cdml">
  <info>
    <author_program version="0.12.2">BKchem</author_program>
  </info>
  <standard area_color="" font_family="Arial" font_size="24" line_color="#000" line_width="0.06cm" paper_crop_margin="5" paper_crop_svg="1" paper_orientation="portrait" paper_type="Legal">
    <bond double-ratio="0.85" length="1.4cm" wedge-width="0.18cm" width="0.21cm"/>
    <arrow length="1.6cm"/>
  </standard>
</cdml>
EOF

cat << EOF > ~/.bkchem/prefs.xml
<?xml version="1.0" ?>
    <bkchem-prefs>
        <lang type="StringType">en</lang>
        <geometry type="StringType">1016x522+4+27</geometry>
        <recent-file1 type="StringType"></recent-file1>
        <recent-file2 type="StringType"></recent-file2>
        <use_real_minus type="IntType">0</use_real_minus>
        <default-dir type="StringType">~</default-dir>
    </bkchem-prefs>
EOF

