Yes, putting the lower rod back farther will help, especially if the tangles are when you hook a fish. A number of tangles will occur if you drop the weights too fast. I typically stop a few seconds about every 15' until I get to the proper depth. This allows the dodger and lure to catch up or flatten out. The longer the setback the more the need to stop. For Kokanee setbacks can be as short as 8' with the lower rod maybe around 20'.
Another option is using a Shuttle Hawk. It's basically a diving plane that takes the upper line/lure down to a stop on the cable. A second advantage is that it can be reset without raising the downriver weight. It works better at slightly higher speeds.
Hope that helps.