We had a bit of a drive round, and went along the coast, then stopped for some fish and chips, so did not come straight back, and yes, the rain was pretty heavy by the time we hit the motorway, and there was a fair amount of standing water.
Look at the LED bars, and put a 24" one across the top of the bar, you just can not beat the LED bars, and being so much lighter, you will have less problems with needing to find a substantial mounting point.