That is!

After some trimings (Plan 3D Normal to the surface(s)
you must make these trims for have all faces permited by the plugin!

(Separe / Boolean Diff a face(s) by a 3D Plane / Join / Plugin / Separe etc...
if you make a normal Trim (not a Boolean Diff) or Boolean Union( against a the good Join) that will not work for the plugin!

You can subdivise again but i don't know what exactly you want because your original form is yet some sweet..

Here with a subdiv 150 sharp blobby result!


subdived 100 gives quasi the same result than your original (just a little more thick) !