That's pretty easy actually and I am doing that already. I tag notes that I wish to be exported with "published" tag. And then change export button script, this part:
"<$list filter="[tag[published]!is[system]]">" -- You received this message because you are subscribed to the Google Groups "TiddlyWiki" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/tiddlywiki/4a4f44ee-78d7-45a3-989d-fb07158baaf0%40googlegroups.com.

