To open the rear hatch with long boats on the roof, i just loosen the rear straps on the rack and open the hatch. No issues as the struts on the hatch easily hold the weight of the boats. In this case I typically out a Thule Landing Pad or a life jacket between the boats and the spoiler to prevent scratches.
Land Cruisers are really made for this.
Land Cruisers are really made for this.