override barline type for entire score

[Kieren Richard MacMillan]

[ Lilypond 2.9.4-3 ]

Hello, all --

Is there a way to change the default barline type (e.g., to dotted)  
for an entire \score? I tried \set Timing.whichBar, but couldn't get  
it to work.

Alternatively (or additionally), how can I adjust the characteristics  
of the standard barline (e.g., make it grey, or dashed, etc.)

Thanks,
Kieren.