Hi
Since nobody else jumped in here's my two cents lol.
I've only dome it a couple of times and only one was successful.. The frond that stays flat the "shield" will develop separate roots and this is a good time top remove them?? I find that unless it's a rare variety (any kind other than (Bifurcatum)it's not worth the effort as you can get well established ones for a couple of bucks at any of the box stores.
Okay you're saying my advice is not worth the two cents??? lol gary