Well, I thought about it. If it was just a single colour warp, I wouldn't mind doing this and those two single grey zingers won't make a big difference.
So I get the idea to do intentionally spare warp threads in the future as back up. How many places can a thread jump in the warp in order to replace a broken one if there are larger sections of a different colour to overcome?
Depends certainely of sett and so one , but as a rule of thumb?