I checked XTRABYTES ann thread, They are having some issues I think so I don't recommend this coin (for now), let them resolve their issue first. but they are having progress regarding their project so let's see what is going to happen.
And In terms of trading the volume is too low, actually it can be a dead coin because no traders are trading this coin. So I can say that, don't trade this coin for now.
Their ann thread: https://bitcointalk.org/index.php?topic=5134924.0
coin volume data etc: https://coinmarketcap.com/fil/currencies/xtrabytes/#charts

And For SAFEX , same issue very low trading volume. I don't recommend it for trading purposes.
I also checked their ANN thread. no team update! So I think this one is not good at all.
Ann thread: https://bitcointalk.org/index.php?topic=1258419.280
coin volume data etc: https://coinmarketcap.com/fil/currencies/safex-token/

For me, don't trade low volume coin at all, that is my basis regarding trading
But if you trust their project, then support them.