First, which version of Lua is appropriate for plugin scripting? says the latest is v.5.3.2. Is the functionality there usable or should I use a previous version (5.1) as Garan points to in his most excellent noob tutorial?

Second, as a matter of etiquette, if I have a specific question regarding code in a particular plugin, is it better to contact the author directly via a private message or reply to a relevant thread the author has initiated?

Thanks in advance.