Replacing Github sheet with a customized one

Quick question that a search didn't yield any answers for me (might not have used the right keywords), I've made a campaign and selected a sheet from Github for it (Ryuutama). The Ryuutama sheet though could use some work, and I'd like to customize and update it myself. The problem is I've already gone and created a lot of Monster NPCs and don't want to possibly destroy all that work by replacing the current sheet with a custom one. Is it possible to replace the community sheet with the custom one, update the custom one, and not destroy the NPC data that already exists? I already tried it out with a copy, and it seemed to work fine, but I want to be 100% sure before I commit.

As long as you don't change the field names, you'll be fine. To be clear...things like... <input type="text" name="attr_hitpoints" />

Coolio, thanks! So the "Attributes" are preserved. Good to know.

Yep. :)

You need a Pro subscription to work on custom character sheets, IIRC. 

Andrew R. said: You need a Pro subscription to work on custom character sheets, IIRC.  I believe a ks backer functions similar to pro subscription (like us forum champions).

Thanks! Now I know, half the battle, etc., ;)

Pat S. said: I believe a ks backer functions similar to pro subscription (like us forum champions). TIL. Oh and the fourth option is to get hired by Roll20, if we going to list all the options. :)

I'm a KS Backer and a Pro Subscriber so I'm covered.