Mounting an rtt on racks attached to a rain gutter?

[Jeep or Tacoma]

I have seen this done. On several vehicles including jeeps which have fiberglass hard tops. Anyone know what the weight capacity of a roof gutter is ?

 

[Sparse Gray Hackle]

I recall a photo in Canoe Magazine of a brace of canoes that rack and all lifted off the top of the car. I’d worry more about the gutter weight capacity than the strength of the towers, they’re fairly robust.