Beyond basic CPU/GPU setup here are a few questions:
1. How mobile do you really need to be? If you really need to be away from a plug for a long time, push for whatever model gives the best battery life.
2. How important is the laptop's screen? If you need the built-in screen to really deliver accurate colors then you might want to shell out more money for the higher-end screens. It's not so much the resolution as the color reproduction that might be important here.
3. Related to 2, if you don't need to rely on your laptop's screen as heavily because you have an external monitor, make sure the display output options are convenient to let you use external displays with minimal hassle.
4. I love SSDs in notebooks, but make sure that if you get one it has plenty of capacity for whatever work it is that you expect to reside locally in the notebook. I guess that depends on if you are just working with linear CAD drawings or are doing crazy 3D modeling with textures and other huge data sets.
I'm generally not mobile with it for more than a few hours. I just want enough flexibility to be able to take the laptop to a client's house for a meeting and be able to make drawings changes, draft render, etc...
I am keeping the display fairly generic with regards to resolution. It seems 4K won't get me much on that screen size, so I can't justify spending extra $ there. I am, however, looking at color calibration where I can.
My storage setup for both options is a 512GB SSD & 500 GB spindle drive. I have an external drive at home for mass storage.
Also, being a fan or just having an appreciation is great! I admire FLW for the fact that he mostly designed everything that went into his projects, like light fixtures, furniture, tableware, etc.... It's quite impressive.