Is it still true from the FAQ and from forum posts a few years ago that to get Skritter to back-fill traditional characters into my study pattern, I have to delete a list that I've completed and re-add it?

It seems from reading this will cause Skritter to re-parse it and add the writing part and recognition part to characters I've previously studied.

Thanks for updates.

Yes. It's still true.

usbrandon, not necessarily. There are 2 different ways to do it, it depends on what is your goal.

1. Learn full-blown simplified and traditional
Set your account to "both", Skritter will tell you, it's not retrospective, but you can chose the list(s) to which this shall apply. I don't know, whether Skritter will continue to add from the current position of the list or go back to the beginning. If it doesn't go back, then go to the list and you'll find below the green study buttons a blue line saying change study setting. Here you can set the position to the beginning of the list. In this mode, Skritter will add traditional for every character or word, which also has a traditional variant. This will quite dramatically increase the number of items which you have to study. It might be fine, if you want to be fluent in both variants.

2. Learn mainly simplified, but also be able to read to some degree traditional
This is, what I am doing; I just want to be able to "decipher" traditional texts, but I will never read a whole book in traditional. For this purpose, I have created a list, which contains all differences between simplified and traditional. These are only around 520 items to study (there are for some purpose duplicates in the list), not the 2000 over different characters. See the list here: http://www.skritter.cn/vocab/list?list=302418553
If you want to study this list, you can do it in this way:
Set your account to traditional and only select this list for study. Then you can add from the iOS app by double-click on the green + sign the number of items you want to have added to your study, say 20 or 50. Once they are all added to the queue, go back to account setting and set your account to "simplified and previously added traditional". In this case, you are getting only these items from the list in traditional, all others in simplified only.
If you want to decrease the number of study items further, you can set your account during the time of adding the traditionals for example to only writing and definition, leaving out pinyin and tones.
In this second scenario, when you are changing the account setting and Skritter asking you to apply this to some list, just reject.