Produce 2no. automated drawings using excel

We are looking to use Excel to automate the production of two drawings. Much of the drawing will just be static so doesn't change but a few things like how many rails there are and the post spacing will need to vary so the macro needs to draw it based on the parameters each time. See the drawings attached which need to be automated where we have produced two examples of each drawing type. We have also added a comments version of each drawing where blue indicates items which dynamically change. We need the geometry to update not just the text. We think this is quite possible using shapes within excel and a macro which builds the drawing with lines, shapes and text. See brief on first page for further details.