Playing with tenses - Past perfect vs Past perfect continuous. I've been learning english for a long time, but I never studied grammar.So by now I'm taking lessons. But I'm a little blocked today. I made this example: Past perfec - “Manuel had repaired many cars before he received his mechanic's license” Past perfect continuous - “Manuel had been repairing many cars for years until he received his mechanic’s license” Now I need to do the same with this Past perfect - “She had never seen such beautiful painting before she visited Sistine Chapel” Past perfect continuous - (((????)))) I tried one, but my teacher told me was wrong, the grammar. “She had been seeing many painting, but nothing as beautiful as Sistine Chapel”

Help me with Past perfect continuous of this sentence “She had never seen such beautiful painting before she visited Sistine Chapel”