Simon comes with all the morphs you need to do this - there is no need to buy any morphs.

I think you may be clicking on the morphing brush tool.

Select the body, then go to the parameter settings. There should be a section labeled FBM (Full Body Morph). That is where you will find the mesomorph dial. This is the body shape you should get (minus the pink speedo).

Sorry - cross-posted!

Poser 11 Pro, Windows 10

Auxiliary Apps: Blender 2.79, Vue Complete 2016, Genetica 4 Pro, Gliftex 11 Pro, CorelDraw Suite X6, Comic Life 2, Project Dogwaffle Howler 8, Stitch Witch