I'm traveling a lot for work and multiboxing while on the road.

I bought asus 502vs few years ago for that. Couple of things I would recommend.
- for GPU nvidia 1070 and anything better is enough (i'm six boxing while on road, 8 boxing when home)
- I'd recommend getting 32G memory. 16 can be done, but it gets easily tight - and once you run our of RAM - like you open chrome, performance drops a lot. Also personally I feel memory was cheaper to buy than spending a lot of time optimizing memory usage.
- Once you are over the threshold with GPU, it seems to be the CPU (and memory) that limits how many clients you can run, what happens on major cities with bunch of people. For me I see CPU close to 100% (and if cooling is not good --> cpu throttles and trouble starts) - i was getting disconnects with some clients when this happened.

Mine has 4 core CPU, now 6 cores and even 8 cores are available, but it can get expensive.

You can get a lot of mileage from optimizing your settings, addons, renderscales etc. But it's effort.

Also test the keyboard, I hated mine on laptop, and ended up travelling with external keyboard