Condemning service - just the right amount (8,4)

I believe the answer is:

critical mass

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'the right amount' is the definition.
The definition suggests a singular noun which matches the answer.

'condemning service' is the wordplay.
'condemning' becomes 'critical' (I am not sure about this - if you are sure you should believe this answer much more).
'service' becomes 'mass' (mass is a church service).
'critical'+'mass'='CRITICAL MASS'

'just' acts as a link.

Can you help me to learn more?

I've seen this clue in The Daily Express.

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