My practice is to bypass the openings and give the market freedom to set up. Once the market(s) sets up and designate current trends, you will have plenty of opportunities to get in without the uncertainty of the openings.
This waiting will support you in more wealth by trading the systems.
Furthermore, markets can also make a move on the opening's first 15 to 45 minutes, then shift and mess up trading for the rest of the day.
I propose to set up your systems XML files and test out many starts and stop times at the same time.
Just add the system a few times and change the times in each set before you run them all and see what performs the best.