What wallet did you use? I managed to get some BTG into Coinomi wallet but can not send it to the address that HitBTC provides.
i used the full node client
Can you import private keys into that client?
How do you know it is safe?
I presume it takes whole 160 something GB to download the chain?
yes you can import keys like in any other Full Node Crypto-Client.
for safety reasons is it always recommended to move your bitcoins to a new encrypted wallet and import keys that should only have some btg on it.
yes you need the whole blockchain.
here i wrote a little tutorial for the official btg-client
https://bitcointalk.org/index.php?topic=2412870.0