Smart Album equivalent of Recent Work in LR

In Lightroom I have 2 "smart collections", one for images with "has adjustments" made to them in the last 30 days called "very recent work" and one for images with "has adjustments" made in the last 6 months called "recent work", which provide a quick way to find images I want to continue working on. I can't figure out how to duplicate this with the C1 "smart album" options. Any ideas?