Roof mounting tandam and single sit on top

Any suggestions for best way to roof mount both a tandam and single sit on top. Can a tandam go on it’s side or would it be too heavy? With thanks

I routenly carry a Tarpon 160 (85#) on my roof rack with a Pungo.
I turn the 160 over and put the other boat in J racks. Sometimes, I’ll carry 3 but that is a heavy load.
I have carried the Tarpon in the J racks but that is almost like having a sail on the roof.

I have a pick up, so the back rack can handle a lot of weight.
But, I have dented the cab , so find out what kind of load your vehicle’s roof can handle.