It all has to end up the same length, so an extra few mm on the cable can only mean and extra few mm taken up by the adjusters. That really isn't going to be a big deal, you wouldn't want them screwed right in or right out, that probably leaves 30 - 40mm in the middle to play with (I don't have any to measure).
Top tip, nothing to do with your question, picked up from someone here or another forum - While you have the bayonet fitting undone, if you haven't already done so, replace one of the grub screws with a cap head, it makes it so much easier to undo and reattach.