I have made an android app for all the duelers and tdm'ers that want to practice their timings.
Myself is a mediocre dueler (~1100-1200 ELO) that wanted to practice something quake'ish when commuting between work and home but also wanted to contribute something the community.
So I made me an spawn item timing practice app. I find it useful to practice MH and armor but also to use it as warmup before going in a duel.
Go to https://play.google.com/store/apps or google play (market) on your android device and search for "quake live timer".
Current android version support is: 2.3.3 and up.
I hope you'll find this useful.