yes sorted out an AUX fuel tank for my toy and used similar. The gap for me with 12 mM braided pipe was 3.03mM according to my verniers! PM me if you need any more information! The easyist thing to do is show you using skype as I could take the laptop into the garage and show you as you asked in real time!

I also use PTFE tape on some of the fitments, as they are for petrol!