Parties don't direct preferences, they do deals on their how to vote cards, whether people follow them or not is up to them.
Palmers voters preferenced LNP / Labor about 65 / 35 in
2019, and close enough to 50 / 50 in
2013 ( 2016 was a no show for the house of reps )
2019 though a lot of his ad spend was attacking Labor, so it would make sense that he'd have attracted more voters that would otherwise have voted coalition anyways. I reckon it was more his ad spend attacking Labor than it was his preference flow that damaged Labor last election.
This election he's running on the idea that none of them are trustworthy nor worth your vote. I think we'll see a closer split on 2nd preferences but still favouring LNP, but that'll mostly be because more voters will desert the coalition than will Labor, not because of any preference deal.
Obviously parties do these because they have some effect, I don't know that it's all that great though. Mind you, a couple of points in the right seats can make the difference between forming government or not.
I guess a lot will depend upon how much primary vote old Fatty Mcf**k Face gets, if it's up in the fives or sixes as some polls are suggesting it could very much influence the outcome, but then if that's the case we're f**ked anyways, cause that's just far too many cooked merkins out there in voterland with a voice.