Well, I imagine the process for 2 would be:

1. Look up glyph in selected language(s)
2. Look for a match
3. Find exactly one match, assign glyph
3a. Find more than one and agonize over which one to pick
3b. Find one, but it already has a meaning assigned, and agonize over whether or not to change things around
3c. Not find a match.
4. Move on to the next glyph

The two big time sinks are the look-up stage and the agonizing stage.  If you think you can cope with those - efficiently looking up natlang glyphs, finding a matching Omya glyph, and not spending too long deciding - that would work.  And if time isn't an issue it barely matters.

It could also provide some good inspiration for method 3 to look through how A Natscript Did It, if you get stuck.