What exactly do you want to know? It's not like users will know a lot more than you, or necessarily where the funds are stored. Me, for example, wouldn't know those details for BitTex even that I use them almost every day. I had used them to dump some Polybius ICO tokens and it was ok, but I wouldn't choose them as my first option.
Limits can be found in Fees and Limits[1]; About safety, I found this on their blog[2]:
We also use cold wallets and store coins safely offline – the cold wallets are secured with multi-key encryption. They are stored in a safe location.
[1]
https://hitbtc.com/fees-and-limits[2]
https://blog.hitbtc.com/how-safe-is-our-bitcoin-exchange/