SAMBA has install manuals for the Stewart-Warner heaters posted -
http://www.thesamba.com/vw/archives/manuals/southwind_68bug_ghia_type3.php
http://www.thesamba.com/vw/archives/manuals/stewartwarner_2_70_servicemanual.php
Not sure how they compare to the German Webasho and Ebersparcher heaters.
Guess you want a HOT car!