Nice object Jumi,

I found three entries for GR 8, starting from 16-inch.

16", 145x, NELM 6m5+
steadily visible with averted vision; round, diffuse glow with 1' diameter; exact form not detectable, interesting object

27", 419x, NELM 6m0+, Seeing IV
direct vision object; slightly elongated with a central peak; very low in the sky

27", 293x-419x, NELM 6m5+, Seeing III
faint but direct vision object; no clear structure but heavily mottled