dzen2 how to detect actual resolution and number of monitors

I use dzen2 with xmonad like this on my laptop:

 h <- spawnPipe "dzen2 -fn fixed -x 0 -y 800 -h 21 -w 1280 -ta l -fg '#ffffff' -bg '#663300' -e ''"

However there are some problems with it.

• If I use an external monitor alone with an other resolution it doesn't stay on the bottom of the screen (I guess since I set -y 800). However it should detect this automatically and position on the bottom of the screen.


• Same with width (for example when using a beamer). However it should set automatically the maximum width.


• If I use multiple monitors it is only on one monitor, but it would be great to have copies of it on each monitor.

How can I fix those issues?