A carbonaceous condrite has the same reflectivity as the moon at around 7-13%.
If there was ice, if the tail was 10 times smaller than hail bopp, it would have auspiciously covered half of the sky. it could have made an incredible display in the 1-2 days preceding the collision, because it was as close to the sun as hale bopp, the brightest astronomical apparition in history, although it was 100 times closer to the earth in the final days than Hale Bopp. Hale Bopps trail was 1.5 million km long, so the KT asteroid would have needed a tail 100 times smaller, to appear as bright as Hale Bopp in the final 2 days! https://www.google.com/amp/s/www.space.com/amp/20354-dinosaur-extinction-caused-by-comet.html
moon distance / moon diameter = the moon is 107 moon diameters away, so you can cover the moon with a thumb at arms length ( ~1cm/107cm) and the impactor would be nearly thumb sized at: comet diameter * 107 = 1500km away.
If you were 1000km south of Chixculub, it would stay fairly constantly thumb sized for 10-20 seconds as it arrived from the South-East at 60 degrees, and in that time it would travel from 1500km above to 1000km on the horizon. The graph suggests it had a rotation period of about 2 to 10 seconds, so it would have revolved noticeably.
If you were 100km away from the impact, it would grow from thumb size to hand sized for 10-20 seconds. Then it would hit the atmosphere at 50km and the sky would ignite about 5 seconds prior to landfall.
For most of the dinosaurs far away it would be like holding a pea or a matchstick at arms length.
Perhaps it would be a brighter than venus from 75000 km away that's about 125 minutes prior to the impact.
It would have been like a fire fly landing slowly on a tennis court if the dino was on the other side of the world.
Mammals were nocturnal previous to the impact which is why mammals have developed whiskers, awesome hearing and only bichromatic photoreceptors of G.B, and mammal skin burns from UV. Only primates have R.G.B.
Dinosaurs had R.G.B because birds have the same gene to encode red photoreceptors as tortoises who can also see red, so scientists think that dino's had vision as good as birds, and have better vision than mammals, especially used for detecting movement and for flying.
EDIT: On wiki, the estimated diameter of the comet has been changed to 10-80km. Hale-Bopp comet was 20-40km, and it was visible for months as one of the brightest comets in human history, with a similar aphelion of 0.914AU. That implies that the dinosaur comet may have been visible for many days prior to impact, because it would have been 5 times closer than Hale-Bopp at the end. It's possible that it was very bright in the sky for a week prior to impact.