Here is CONUNDRUM #6 - it is has the HIGHEST Total Value that I can find in the Merriam Webster Online Dictionary:
_ _ _ _ R _ U S with a
TOTAL VALUE of 156.
There is a higher Total Value of
170, which is the highest I am aware of for an 8-letter word, but unfortunately it doesn't appear in the Merriam Webster Online Dictionary.
Good Sleuthing.