Camera view is too fast? So I'm working on a model which was previously huge so I downscaled it to a reasonable size but now I've encountered a problem with the camera. Normally I could slowly zoom in to work on details but now the camera moves way too fast and basically flies through the model.

I googled this and noticed someone mentioned "center of project" and I was wondering if anyone could further explain this and how to fix it? Also I know the Alt and Ctrol and Shift for controlling the speed of the camera but this has stopped working as well.

Also due to copyright reasons, I can't upload any part of the model. Sorry guys :(
If i get you correct, you are trying to move around the project using Shift+F,

If you are trying to zoom in and out, try Ctrl + MMB (Forward and backwards to zoom in and out)

Also if you want to edit specific area, press Keypad - . to zoom in to edge/ face or vertex after selecting them.

Set the clipping area of the camera to lowest-or 1mm (camera of the viewport, not in your actual camera which you use to render. Select N in you 3d space. you will get a menu on the Right*, from that look down towards middle to reach Clip options)