Yes, going too slow can have two major consequences: 1) the towed can drag on the bottom of the ocean if it's shallow enough and you'll have washout, 2) the towed can dip beneath a layer if you're above a layer, which can be a desired behavior, but not if you weren't planning for it lol.
Also, the slower you go, the longer it takes for the towed to turn and straighten if you order a course change. When the towed is turning (re: not straight), you can't trust the data from it. I recommend streaming generally only 25-33% of the length of American toweds, and approximately 220 m for Russian toweds in order to reduce the time it takes for the towed to straighten.
Thank you for taking the time to make these,, very helpful,, in giving CW a run for it's money but we will never beat the graphics ,, drool