What placement of plasmid parts makes the most sense?
The relative placement of genes on a plasmid should not affect their expression. 

Both will be expressed and to what extent is dependent on the strength of the promoters and a few other factors like codon availability.

However where you ultimately plan to express these genes can be an important consideration in plasmid design. For example, if you are designing a binary vector for agrobacterium mediated transformation of plants then positioning the plant resistance cassette next to the left border is a sensible move.