How detailed is KYB for Proprietary Firms?

I'm looking at several prop firms lately, planning to try and get some capital to trade $EM. But I see that each firm's KYB process is quite intense. Some ask for more than opening a brokerage account. So I want to ask friends who have gone through these applications, what is the detail of the verification like? Does it take a long time? Are there any documents that seem more complex than usual? I'm concerned about delays because I want to start soon.