'opsz' information from Garamond Premier Pro fonts, as reported by otfinfo -z and sorted by design size and subfamily ID:

GaramondPremrPro-Capt.otf       design size 6 pt, size range (6 pt, 8.9 pt], subfamily ID 1, subfamily name Regular
GaramondPremrPro-MedCapt.otf    design size 6 pt, size range (6 pt, 8.9 pt], subfamily ID 2, subfamily name Medium
GaramondPremrPro-SmbdCapt.otf   design size 6 pt, size range (6 pt, 8.9 pt], subfamily ID 3, subfamily name Semibold
GaramondPremrPro-BdCapt.otf     design size 6 pt, size range (6 pt, 8.9 pt], subfamily ID 4, subfamily name Bold
GaramondPremrPro-It.otf         design size 6 pt, size range (6 pt, 8.9 pt], subfamily ID 6, subfamily name Italic
** should be design size 11 pt, size range (8.9 pt, 14.9 pt]
GaramondPremrPro-ItCapt.otf     design size 6 pt, size range (6 pt, 8.9 pt], subfamily ID 6, subfamily name Italic
GaramondPremrPro-MedItCapt.otf  design size 6 pt, size range (6 pt, 8.9 pt], subfamily ID 7, subfamily name Medium Italic
GaramondPremrPro-SmbdItCapt.otf design size 6 pt, size range (6 pt, 8.9 pt], subfamily ID 8, subfamily name Semibold Italic
GaramondPremrPro-BdItCapt.otf   design size 6 pt, size range (6 pt, 8.9 pt], subfamily ID 9, subfamily name Bold Italic

GaramondPremrPro.otf            design size 11 pt, size range (8.9 pt, 14.9 pt], subfamily ID 1, subfamily name Regular
GaramondPremrPro-Med.otf        design size 11 pt, size range (8.9 pt, 14.9 pt], subfamily ID 2, subfamily name Medium
GaramondPremrPro-Smbd.otf       design size 11 pt, size range (8.9 pt, 14.9 pt], subfamily ID 3, subfamily name Semibold
GaramondPremrPro-Bd.otf         design size 11 pt, size range (8.9 pt, 14.9 pt], subfamily ID 4, subfamily name Bold
GaramondPremrPro-MedIt.otf      design size 11 pt, size range (8.9 pt, 14.9 pt], subfamily ID 6, subfamily name Italic
** should be subfamily ID 7, subfamily name Medium Italic
GaramondPremrPro-SmbdIt.otf     design size 11 pt, size range (8.9 pt, 14.9 pt], subfamily ID 7, subfamily name Italic
** should be subfamily ID 8, subfamily name Semibold Italic
GaramondPremrPro-BdIt.otf       design size 11 pt, size range (8.9 pt, 14.9 pt], subfamily ID 8, subfamily name Italic
** should be subfamily ID 9, subfamily name Bold Italic

GaramondPremrPro-Subh.otf       design size 18 pt, size range (14.9 pt, 22.9 pt], subfamily ID 1, subfamily name Regular
GaramondPremrPro-MedSubh.otf    design size 18 pt, size range (14.9 pt, 22.9 pt], subfamily ID 2, subfamily name Medium
GaramondPremrPro-SmbdSubh.otf   design size 18 pt, size range (14.9 pt, 22.9 pt], subfamily ID 3, subfamily name Semibold
GaramondPremrPro-BdSubh.otf     design size 18 pt, size range (14.9 pt, 22.9 pt], subfamily ID 4, subfamily name Bold
GaramondPremrPro-ItSubh.otf     design size 18 pt, size range (14.9 pt, 22.9 pt], subfamily ID 6, subfamily name Italic
GaramondPremrPro-MedItSubh.otf  design size 18 pt, size range (14.9 pt, 22.9 pt], subfamily ID 7, subfamily name Medium Italic
GaramondPremrPro-SmbdItSubh.otf design size 18 pt, size range (14.9 pt, 22.9 pt], subfamily ID 8, subfamily name Semibold Italic
GaramondPremrPro-BdItSubh.otf   design size 18 pt, size range (14.9 pt, 22.9 pt], subfamily ID 9, subfamily name Bold Italic

GaramondPremrPro-Disp.otf       design size 72 pt, size range (22.9 pt, 72 pt], subfamily ID 1, subfamily name Regular
GaramondPremrPro-MedDisp.otf    design size 72 pt, size range (22.9 pt, 72 pt], subfamily ID 2, subfamily name Medium
GaramondPremrPro-SmbdDisp.otf   design size 72 pt, size range (22.9 pt, 72 pt], subfamily ID 3, subfamily name Semibold
GaramondPremrPro-BdDisp.otf     design size 72 pt, size range (22.9 pt, 72 pt], subfamily ID 4, subfamily name Bold
GaramondPremrPro-LtDisp.otf     design size 72 pt, size range (22.9 pt, 72 pt], subfamily ID 5, subfamily name Light
GaramondPremrPro-ItDisp.otf     design size 72 pt, size range (22.9 pt, 72 pt], subfamily ID 6, subfamily name Italic
GaramondPremrPro-MedItDisp.otf  design size 72 pt, size range (22.9 pt, 72 pt], subfamily ID 7, subfamily name Medium Italic
GaramondPremrPro-SmbdItDisp.otf design size 72 pt, size range (22.9 pt, 72 pt], subfamily ID 8, subfamily name Semibold Italic
GaramondPremrPro-BdItDisp.otf   design size 72 pt, size range (22.9 pt, 72 pt], subfamily ID 9, subfamily name Bold Italic
GaramondPremrPro-LtItDisp.otf   design size 72 pt, size range (22.9 pt, 72 pt], subfamily ID 10, subfamily name Light Italic