Hi!
I’ll try to help you a little bit
1. I’m using separate hood. SFTech uses my favorite K01. I have 3/5/7mm. I used 7 last time for my 90 minutes 70m dive in 4 degrees. It was fine. My Drysuit has silicone neck seal and it was still ok. I wouldn’t take attached hood - but that’s me
2. The neoprene seals properly. And it’s warm. The only reason I’m not using it is that I cannot change it by myself.
3. Ask SFTech directly. Franz is super helpful.
4. Get the TNT Pro version. It’s warm enough and super comfy. I’m using SFTech heating pads with their vest and thickest MolaMola under suit. And I’m pairing it with Ammonite Thermal battery. Works flawlessly.
5. If you used their Polartec undergarments then they are pretty thick. You don’t anything thicker.
6. I prefer not to use pockets when SM. I use back pouch.
And on top that - yes, it’s the best drysuit I’ve ever used
Cheers