Same size will never work even if printed separately. Best to print a test cube (or similar) and get the calipers out to check. I have found it could be 0.1mm thicker than modelled in one direction of print (squeeze effect) but bang on in another. The other aspect is design clearance, tight fit that is permanent, tight that will loosen with time (wear) or loose fit from day one. Experiment, there is no hand book on this