It’s not likely, but is it possible to duplicate a weighted vertgroup say on the left leg, and then apply it to vertices on the right leg, and leg armature. If it’s possible please explain, this would save alot of time.
weight paint and configure groups for one half of your character
duplicate, mirror [in edit mode around the cursor], and rename all the vertex groups to .L or .R from .R or .L…
then join with the original and remove doubles