I'm not sure if I follow how you play either, but the title intrigued me because I'm also left footed. I can use both as I need them, but only the left is the instinctive foot - the right I have to think about what it's doing.
My kit is setup a bit differently though.. basically a left handed kit with a right bass drum and hi hat. It is open handed, ride is on the right. Toms roll down to the left thought I'm always fiddling with their placement.
When I'm using a single BD, I use a traditional right footed double bass pedal and have the BD on the right side. The left/slave pedal is the primary pedal. I use a BD->hi hat clamp (like this http://www0.shopping.com/xPO-Pearl-P...rum-Attachment
- it was a lot cheaper than getting a good lefty DB pedal) so I can keep pedals next to each other.