Premial means serving to reward or rewarding.
I came across it in Smeaton on the atonement who uses it several times as in "the premial life which awaited man after a period of probation". Could find no literary references except one in essay on educatio by De Quincey but I came across this interesting blogpost here.
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.