Ok, so if you like me are fed up with all your merchants making nothing on resources then do the following
within your bc folder go to data and then the descr_campaign_db.xml file. Covert to a .txt file for editing and then look for the line <base_income_modifier float="1.0" />
alter it and convert back to .xml. The change will take effect in any current game so you do not need to start again.
changing this number will mean that rather than 26 gold for a resource you can get maybe 100 etc. The higher the number the more you earn. Though of course this applies to ai-merchants as well.
This can be applied to any mod. Don't forget to back up files before changing them.