So here's my question then. If I wanted to maximize damage protection while also not being totally cucked with no movement points, what would be the best setup for that? What metal should I use? Is armor sloping worth it? What if I just rock metal armor with some Tabi's/Leather Boot Springs, and a Psionic Headband? I want to be able to tank some reasonable after 18 or 20. Also, my char currently has 7 Constitution, is that enough Con for a tanky build? Any suggestions welcome since I've never done a heavy armor build before.
If you want absolute max protection with short periods of decent mobility, full 95% armor penalty tungsten set with sprint, contraction and jumping bean is the way to go. Sprint is 30 MP, contraction is another 30 and jumping bean is 10, all unaffected by armor. You can trigger each as needed or combine them for 3 turns of 70 MP. Don't bother with sloping or nimble in this case, you will be way over 95% anyways.
You can also do what is commonly known as a nimble can - super steel armor with sloping, nimble and optionally body weight training if you have the STR for it. That's somewhat tanky at only 14% AP with just the metal armor. 4% with body weight.
7 is kinda low for an actual tank, I'd say 9-10 is the go-to. But if you compensate with pig/bison tabis, have the WIL for stoicism, take other tank feats like juggernaut/conditioning, it will work fine, if not optimally.