This is a pretty easy calc. Collective Man has the force of 1 billion people/the population of China. Spidey can tank his punches, at least when in his Mark IV Armor. Human level is 40-100 Joules, so the median is 70 joules. There 1.386 billion people in China, so we multiply the 2 and get 97,020,000,000 Joules. There are 4,184,000,000 joules in a ton of TNT, so we do some division and get 23.1883365200764818 tons. 8-B is 11 to 100 Tons, so this is 8-B. It could be argued he downscales due to seeing quintuple, but besides that he was pretty much fine and I'm pretty sure it's still 8-B.
Edit: Actually, I'm going to redo this with 1.142 billion people since children or whatever would be 10-C, but there are 1.142 billion adults. We get 79,940,000,000 joules, divide by 4,184,000,000 (to convert to tons of TNT) and get 19.1061185468451243 joules. Yes, he still downscales, but I wouldn't say below 11 Tons of TNT.
Edit 2: It was in All-New Inhumans #6
Edit 3: I'll just do 1 Billion as well. 1 Billion x 70 = 70 Billion. 70,000,000,000 joules is 16.7304015296367113 tons of TNT, so still 8-B. Yeah, every single calc is 8-B.