RE:$5 a barrel? 8? What is a good amount to reconcile the diffTo answer your question another way...
WTI:AWB spread will be a little larger than the WTI:WCS because AWB is a more sour blend. I saw one report that the spread was about $2 at the gulf over a quarterly period.
With regards to removing the dilutent and comparing the realized Bitumen price to WCS makes no sense since WCS also contains blended products which would be specific to each producer.
But if you really want to know regardless, subtract the dilutent cost per barrrel - I believe between $9 and $10 - the precise figure is in the last earnings report, and then subtract a further $2 for the reason I mention above.