I think BTG is not that good to buy from your BTC. Its trading around USD 140 looks it is not stable.
If you not sell any bitcoin gold (BTG) you received from folk for free. don't sell those now the price is around $140. If you already sold those when the price is above 300USD you are a winner. ;)
This is not a buy recommendation & if you are a high risk taker and only if you can bare a loss you can try with small amount