Yeah exactly that. Running up to approximately 8kg/mm all around should still be quite street friendly. I can't see the calculator now as I'm on my phone, but an 8k spring will decrease your chances of bottoming on unexpected potholes. 8k was simply an estimate and also everyone's classification of street friendly will differ.

When you get a spring compressor, try and use the hook type. I used a flat angled surface spring compressor and it would slip alot. It was my first time using one, so perhaps this contributed.

I'm unsure if my assumption is correct, but a bigger swaybar will add roll stiffness/resistance, similar to using a stiffer spring. I would imagine this to be providing extra prevention to bottoming. However with your situation, that would apply to the rear end.