Hi Gary managed a view tonight 15 mins either side of moonrise and start of astro dark. Used 8 x 42 bins then my 4″ F9 Fluorite refractor with a 50mm Tak LE e/p giving x18 and almost 3 degrees FOV, but more importantly pin point star edges to the edge with this combo. Using your 5 degree chart, Chi was definitely brighter than C (mag 6.2) but very similar to B (mag 5.9) or if anything a tad brighter, the difficulty being the colour difference, Chi being reddish orange and B white. So I would put Chi at mag 5.9 to mag 5.8 tonight.
Andrew