If I convert a bike to a single speed/fixed and decide to leave the double ring on the front, is there any reason I should use the bigger or smaller ring? Should I just find whatever gear feels good and go with that one?

I might convert and old LeTour this weekend. It has 2 rings in the front and 5 in the back. The gear I found I liked was small ring in front - 2nd smallest in back. I don't know what sizes they are.

I figured I could leave the front double on just to go as cheap as possible (not a lot of extra cash right now). Other than weight is there any reason to not leave the double?