Honestly, I don't know the answer to this question.
One option I can say is impossible is to help feiglin get elected. The Likud list order has already been set and he earned his spot # in the primaries, so as long as Likud gets x number of seats, Feiglin will have a seat. I think Likud having more than that number x seats is almost 100% likely at this point, so Feiglin is going to have a seat regardless. The major legwork for his campaign is always done in the primary. I don't think he benefits at all from Likud having more or less seats as long as its over the threshold where he has a seat. I would very much like to see him have a seat in the knesset this time around. But that in itself certainly won't be enough. But I want to see what he will do with it. I'm partial to feiglin but if I was in Israel right now I still would not vote Likud in the election.
I am very hesitant to speak positively about Mafdal or even about Otzma Lyisrael. That said, even if Otzma is one of these flash in the pan type things that's going to disappear or reformulate yet again in a few years from now, in a way I would like to see them get a few seats because they might cause some ruckus. I don't quite understand their agenda, nor do I agree with much of their views, but I do like the fact that they are willing to sometimes say things against the establishment. That is moreso Eldad than ben ari in my opinion. If they have a couple of seats it might help them grow a pair and be more bold. I don't know.
Edit to add: Wow, I just saw Chaim's latest video about Otzma defending the nazi Tibi. I give up.