We find good results if we set the chaffer about 3/4" open, and the sieve roughly the same (you can fine tune it after), slow the cylinder speed as slow as you can go (to prevent mechanical damage to the peas) and open your fan up quite high can give you a nice, clean sample. We set our fan at setting 4 or 5 on a R75. Also set your concave (front and back) around 3/4" clearance. That you should give you a reasonable place to start. Hope this helps.
I wouldn't run the rotor to slow. if you do it can tend to wrap the peas and "auger" them through with out threshing them. I found 300 rpm to work well and not crack to much. we had less than .5% splits and we combined them at 12-14% moisture. That was with pfp rotor and the concave fairly wide open.
Don't forget to close the slides down on the unloading auger. We didn't and the first time we started to unload at anything less than full throttle, we plugged the unloading auger and burnt the drive belt off.
For tough conditions I've allways found the tighter the concave the better. Speed cracks more than clearance. So if you start out at 3/4" as above don't be afraid of cranking down and down if your getting a grumble and rumble with split seeds the result. Of course the more hyped you have that 62 the better off you'll be (steep thresher helicals, forward cylinder bars, rotor sweeps, ect.)