This melody from Liber Hymnarius, 1983, p. 190 is well attested in multiple older manuscripts

Yes - there are two well attested "ferial" tones for matins hymns, this one and the more simple one that I selected for all ferias. This one is used for Primo dierum omnium on winter Sundays. We could make it an option for all ferias, or indicate that all ferial hymns can be sung on this tone with a rubric.