SCI_WORDRIGHT and SCI_WORDRIGHTEND are commands, which one is used can be controlled with the 'use_gtk_word_boundaries' preference.
Not quite sure how to change that preference, or what it means...
SCI_SETWHITESPACECHARS can be changed in filetypes.common with the 'whitespace_chars' setting.
I've shortened the setting in filetypes.common to this: whitespace_chars=\s\t([ Feels much better already - not perfect (e.g. it doesn't stop at the end of a line, and even skips blank lines completely), but it'll do.
FWIW, here's the snippet I've tested this with so far:
# Python def foo(): print bar
// JavaScript function foo() { alert(bar); }
Thanks again!