The nearest expiration date for LLS (Argus) vs. WTI Financial Futures (May 2017) is Jun 1, 2017.
The best time to sell a futures contract is when you've already made money on the investment, but still have plenty of time left before the expiration date. Thus, a good option would be to sell LLS (Argus) vs. WTI Financial Futures (May 2017) before Jun 1, 2017.