Fair enough, finally getting somewhere. I have only seen the most common method, similar to the GL? " imitate the GL500 style swing arm and mount from in front of the rear wheel up to the spine"Yeah, but... this will require an understanding of the force and moment applied to the shock, as well as the total travel, dampening, and spring rate.
Are you going to hoop over the rear wheel, with a shock between that and the spine?
Are you going to imitate the GL500 style swing arm and mount from in front of the rear wheel up to the spine?
Are you going to have a pull-type shock linkage mounted under the engine?
Do you weigh 120 kg with a 100kg pillion? Or will you make it a single seater?
Like Murray said, come with a design that can be evaluated, not just asking for the answer to an equation you haven't given.