Relationship between plasmid size and amount of lipofectamine needed? - (Jul/07/2014 )

Is there a correlation between DNA:lipofectamine ratio, plasmid size and transfection efficiency? Is it as simple as a small plasmid needs less lipofectamine and larger needs more lipofectamine for efficient transfection? Larger the size the more is needed? I feel that it is more complex and needs to be determined empirically or the reagent protocols would specify plasmid size. Just trying to figure out why the ratio and DNA amount needs to be optimized for each plasmid. Or does the amount of lipofectamine just vary by the plasmid?  A large plasmid may need less lipofectamine than a smaller plasmid or vice versa. 

Thanks!

In my experience, it is relatively rare to have to go outside the 3:1 used for most plasmids.  I don't think there is a relationship between plasmid size and amount of lipofectamine, but perhaps there is something related to the overall charge on the plasmid.