Currently what I'm doing for speed/efficiency:
1. Compile (my Eclipse compiles on save)
2. JShrink GUI -> reopen "class" file, then save it as a JAR.
3. Pack200 the resulting JAR:
pack200 -G -E9 -r G.pack200.jar G.jar
Sometimes I throw Proguard into the mix, but it tends to be pretty slow and annoying to use during development.
Proguard settings (Mac):
-keep public class G extends java.applet.Applet
Once I start getting closer to my byte budget, I'll probably have to experiment with some other compression techniques...