How many disruptors would I need to add valentine lace to my 6vis breeding project? What pets should I use them on (what generation?)?

Well, as with any trait you need at least one pet with the trait for your project, so the minimum would be one disruptor. I typically like to add the trait as soon as possible so it can start spreading through the offspring right away, but really you can add it at any time.

Vlace is nice in that there is only one slot you have to worry about. You just need a visible trait for vlace to replace and either have g3 empty or the vis trait you are replacing in that slot. I like to put restricted traits on males if possible so they spread faster, but again it isnt strictly necessary. With the restricted trait philters that add in multiple slots I take what I can get, gender wise.

Hope that helps,
Fae

That does help a lot, actually! But can I have a carried trait in the slot I want to use the disruptor on, or does it have to visible or empty.
And if It works in a carry trait slot, will Valentine lace be carried or visible?

there cannot be a carried trait in a slot you want to be replaced by a disruptor. The slot must be either empty (free) or have a visible trait in it (which it will replace)

Carried traits are ineligible for replacement.

Okay, thank you!