First off, congrats on picking the institutional index! That has an amazing expense ratio!
I think step 1 is revisiting your Investment Plan and/or desired asset allocation. Step 2 is picking the fund(s) that match your desired asset allocation.
Since you have several ultra-low-cost index funds available to you, in your shoes I would go with something cheaper than the Vanguard Cap Opportunity, but since it is still less than 0.5% expense ratio, it's by no means a bad choice, if that is where you need to be to match your desired asset allocation.