You may find this address by Dr A Donald MacLeod on writing Christian biography of interest. His books include biographies of C Stacey Woods and W Stanford Reid (obviously drawn to them as like him they didn't go by their first names :-)).
Bonhoeffer uses a similar phrase 'worldly Christianity'. It's J Gresham Machen that I want to line up most closely with. See his Christianity and culture here. Having done commentaries on Proverbs (Heavenly Wisdom) and Song of Songs (Heavenly Love), a matching title for Ecclesiastes would be Heavenly Worldliness. For my stance on worldliness, see 3 posts here.