performing an extraction with each small amount separately may or may not give satisfactory results depending on the specific potency of those specimens.  It might be more trouble than it's worth to do this at those quantities.  Perhaps SWIY could consider making a tea with each species separately or possibly encapsulating each separated amount.  This would be a good indicator of potency and allow one to experience the subtle difference of each without performing an extraction. 

Even if one combined the two for a 50g extraction, one wouldn't expect a huge yield and in addition the unique qualities of each would be lost.  These are just SWIM's thoughts.