Do some 3D Modelling

I have two 3D scans of a human torso that need to be manipulated. For each torso I want to 3D print two objects. 1. The Human torso which has a piece of its neck removed. 2. A mould which can be used to make gelatine casts (to replace the missing piece from 1.) The attached sketchup files contain a cube which has been orientated to perform a Boolean subtraction from the original intact human torso. After completing the Boolean subtraction, the piece of the neck which has been removed will need to be further modified so that it can be used as a mould (after 3D printing it will be filled with liquid gelatine. The final torso (after subtracting the “missing bit”) and the mould will need to be adjusted to reduce the cost of 3D printing…Each will be a hollow mould with 3mm thickness. Each large torso will also be perforated with multiple 1mm diameter holes in a uniform pattern to further reduce the cost of 3D printing. I have attached an initial example/attempt for torso 1….it might explain better….. The mould needed bounding walls on 3 sides to allow it to be filled with liquid (1mm holes not yet added) $50-75 USD 2-3 days