In Rhino we have two places:
The model space, where we model our 3d objects/2d curves. In this place everything should be at 1/1 scale, which mean that if you have a 10x10m house, and you mesure it with the distance tool, those are the values you should get.
In this model space, you can also generate drawings from your 3d objects using Make2D as you already did. There are two kinds of outputs generated by Make2D, parallel views and perspective views. The former should also be at 1/1 scale, and you should make sure of that by using the distance tool after running Make2D and scaling accordingly in case the result wouldn’t match. Then, we have perspective views which don’t have scale and you shouldn’t be worry about how big they are because you will solve that in the next step.
The layout space is where we produce and compose the drawings on actual pages, in your case A4. The link between model space and layout space are details and you can have as many as you want on a page.
Neither of those, you shouldn’t scale anything if everything is 1/1 as we did in step 1. The way you solve this is by adjusting the scale of the detail. So, you have your base properly adjusted on the A4 and now you have to place your new curves from Make2D on that page. Create a new detail by using the _Detail command and draw the rectangle, then select the outline by Left clicking on the outline once, and in the properties panel adjust the scale until your drawing fits properly
Does this help you? If not uploading a file would make thing easier to understand and solve.