My friend made one from a 3 ton shop press because he explained that higher pressure gives a bigger yield, meaning more rosin separated from the mesh bag, less of the rosin still soaked in the leftovers.
If that's true, and if it's not acceptable that you can still use the leftovers by soaking in everclear because you want the straight rosin, like for dabbing, then you want as much pressure as you can afford.