One of the most well established imposition applications is Preps, currently by Kodak. It will do what you need and then some. In fact, it is overkill for your described need, and expensive! But if you routinely do the size of jobs you mention, you probably can afford it over time.
But it also sounds like you could learn more about what to do with the 4 up printed press sheets, because that can directly dictate how you impose the pages. For instance: why are you putting only fronts on one side and backs on the other? Are these being cut apart and then flat gathered by some means? You should consider creating 8 page signatures (folding sheets) with your imposition application, Preps or any other, and this will make for 1/4 as many pieces to be gathered.
Of course they will require putting them through some folding machine, either on your premises or some other. But notice that a 600 page document goes from 300 cut apart pages to be gathered, to 150 folded sheets, called signatures, to be gathered. And this folding process can be done with only one folding machine set up, and will require gathering (collating) i/4 as many pieces.
It may be that you already knew some or all of this, but it did not sound like it from your earlier posts.
Al