My single turbo Wayfarer Ute build

clear as mud Wardy LOL. i'll upload the 6530 disc to my laptop and have a looksee and try and get familiar with it. what you have said does make sense.

the wastegate came with a 15 psi spring. the top fitting is basically not used in my app then, so can I plug it or should it stay vented.
do I need to put a fitting on the turbo cold side housing. this would need to be done now if so before I button things up.