If you are using Nauticam clamps, they offer a version called a multi-purpose clamp, that has a place to insert a 1" ballt, so as to allow the mounting of a second light next to the strobe, or, if you want to separate them, you can use the multi-purpose clamp with the ball as the middle clamp between the two arms, so the video light will be at the joint between the arms and the strobe at the end of the arms. Check it out on the Nauticam website.
Or, and I did this with my pair of YS-01s and Sola 4000s, you can put a ULCS triple clamp at the end of your arms, and mount both the strobe and light right next to each other. The length of the ball mount on the strobes/lights allowed plenty of clearance but still placed them right together in an over/under configuration. I put the video lights on top. That way, when you are shooting stills and position the strobes, and want to switch to video, the video lights are already in the same position. Also vice versa. I found this very easy and fast to use underwater. Above water, having all that weight at the end of the arms made handling a little tricky, but the clamps could tighten down enough to prevent excessive movement. By the way, you can also use the triple clamp as the center clamp if you want to have the video light on the center clamp.
If you google nauticam multi purpose arms and pick "images" you will see photos of the set-ups with the video lights on the center clamp and strobes at the end, and also images with both on the end clamp. You can easily visualize the same set up with the ULCS triple clamp.
Personally, I found the ULCS triple clamp a more compact, elegant and simple solution.