my findings usually are

KLM/AF

AMS-XXX - Intra european Y Roundtrip - 10 XP = 89-140 euro (default rate)
AMS-XXX - Intra european J Roundtrip - 30 XP = 700-950 euro (compleet horsecrap imho)
AMS-CDG-XXX - Intra european Y roundtrip - 20XP = 200 - 400 euro (bad rate)
AMS-CDG-XXX - Intra european J roundtrip - 60XP = 400 - 550 euro (acceptable)
XXX-AMS-CDG-XXX - intra european J roundtrip = 90XP = 450 - 600 euro (if found < 500 euro a steal)

AZ

XXX-FCO/LIN-XXX - intra european J roundtrip = 60XP = 300-400 euro (good deal if not expensive on stays routing).


AF/KLM

on Longhaul with good puzzling you can manage to make XXX-AMS-JFK/LAX/ATL/DTW/BOS/MSP-XXX for around 400-500 euro in Y which yields 34 XP roundtrip. but then u fly widebodies to the USA. if for example XXX-AMS-JFK/DTW-YYZ 40XP for 400-500 is doable.

Longhaul in J besides the specific runs u could do XXX-AMS-CDG-USA or XXX-AMS-CDG-USA-USA for around 2000 euro in J which yields around 132 XP depending on route. Which is around 15 euro / XP but then u have the "true" business class product instead of the empty economy middle seat in front of the plane business class.