A truer answer to this question may require an expansion on what your plans are for trading futures. I reckon OI and volume have their places among any number of trading strategies. One may not be mutually-exclusive to the other.
Expound upon your ideas and you might find clearer guidelines from the folks here.
I don't intend to use futures for day trading. I intend to use them for longer-term trading as a speculator. Embarrassed to say, I have yet to place even a single trade on futures. I have been investing in stocks in the past. Now, I am still studying futures.