When I am using DomainKeys and DKIM together on a linux system, do I run both of them on the same port?

DomainKeys:
/usr/bin/dk-filter -l -p inet:8891@localhost -d example.com -s /var/db/ domainkeys/default.key.pem -S default

DKIM:
/usr/bin/dkim-filter -l -p inet:8891@localhost -c simple -d example.com -k /var/db/dkim/mail.key.pem -s mail -S rsa-sha256 -u dkim -m MSA

Or do I do something like this:

DomainKeys:
/usr/bin/dk-filter -l -p inet:8892@localhost -d example.com -s /var/db/ domainkeys/mail1.key.pem -S default

DKIM:
/usr/bin/dkim-filter -l -p inet:8891@localhost -c simple -d example.com -k /var/db/dkim/mail2.key.pem -s mail -S rsa-sha256 -u dkim -m MSA

Just wondering since information about DomainKeys and DKIM tell you to run them on the same port:
http://www.elandsys.com/resources/sendmail/domainkeys.html
http://www.elandsys.com/resources/sendmail/dkim.html

I want to run both of them together, is this a bad idea?