Hi :)
Thanks, I appreciate it that you like the extension :)
Sorry for the late answer, totally forgot to answer it :)
You can check such things here: https://forge.fantasygrounds.com/shop/items/1/view
When effects have a (T) in their description, then they're targetable and can be combined with IFT as you want. However, DC is sadly not a targetable effect, so that won't work. That applies to all IFT thingies, also the nodex one :)
That is due to the structure in the code, but I can check again :)
As a manual workaround: You could give the targets a SAVE: -1 effect combined with an IFTAG using a tag which only that caster has who has the higher DC :) (if it comes from a usable item, then that could be an effect action of that item) But I certainly see why a DC effect would be more comfortable; but I cannot promise whether I can easily add that :)

