I'm doing this right now after machine re-assembly but I'm waiting for new planer knives so haven't done the full test yet. My machine has adjustable locknuts which set the lowest possible position of the rollers relative to the cutterblock.
Initially I've set up infeed and outfeed rollers 2mm below the cutting circle. Obviously they both lift a bit as the timber goes through. Then I ran a 16" wide board through with the belt off the cutterhead to see if the feed is straight, I found I had to adjust the tension springs a little before the board would travel straight through without skewing. But it was easy, just tension the side that is lagging behind the other.
My p/t also has pressure bars, also spring loaded, not sure what height they are meant to be but judging by the smoothness of the infeed pressure bar, it must have been touching the timber before it met the cutter. The outfeed pressure bar I've set a millimetre above the cutting circle so it doesn't mark the planed surface. Actually, I'm not really sure what they're for. I think maybe they form a sort of chamber to channel chippings up through the gap between the two planer tables.
If I find, when I do the cutting test, that the timber won't feed I'll increase the tension on the springs on both sides. If I get infeed roller marks I'll raise the infeed roller.