Res: [tied] g^H: an older suffix in PIE adjectives?

Analysing a set of Greek adjectives it's possible to detect many patterns: most of them fit into three groups:

1) zero-grade-root +-u : bradys, brakhys, platys, takhys, pakhys, drimys, thrasys, barys, elakhys, glykys etc, probably polys, he:dys
2) zero-grade-root +-ro: hygros, elaphros, pikros, mikros, makros, hadros (and maybe auste:ros, xe:ros, liparos) (cf. Latin scaber, glaber, vafer)
3) zero-grade-root +no : iskhnos, pyknos, kainos

This no- and ro- names must come from -n/r names. Many of the u-names in Latin gained i-augment: levis, brevis, gravis, suavis, pinguis.
JS Lopes