I trade mostly stocks,SPY ,IWM options.
Correlating to oil, I trade 3 distinct different oil sub group stocks.
Integrated/refiners/gassy stocks/Drillers/OSX service providers etc
Because XOI/OSX does diverge with crude movement,recently strted trading USO to mimic CL. (same way GLD /gold futures)
Even though I have CL in my screen, I trade USO ( it lags very badly to CL front month because of management costs & roll over costs)
I can trade USO in 100 share increments (even 50 shares some times). works only with low cost broker like IB.
Averaging in to a say $ 2 down move is risky.But works most of the time!I will go up to 1000 shares on a 2 day down trend.
Nibbling small quantities initially & when indicator is strong I buy larger lot.
Volume is decent in USO. For every $1 movement in CL, you may get around 0.60 to 0.70 in USO. latest gas fund is UNG .