5.6mm or 7mm Fuel line & breather pipes? Fire prevention help pls

I posted this in an old thread but am struggling to get answers and I need to order bits soon.
My engine is about to come out, please can someone confirm if this is a correct list of bits that need checking/ replacing, in terms of fire prevention:
Type 1 engine in a 72/73 bus
Fuel tank breather pipes including ones behind engine firewall. R9 rated pipe at 5.6mm or 7mm internal diameter?
The Pipe behind the spare wheel, plus pipe from the output of the tank to the fuel pump?
What sort of clips/clamps are needed? (Baysearcher has kindly said not to use jubilee clips)
I don't appear to have the t piece. I'm on twin carbs and an oil breather box, where would it be best to vent the fuel breather pipe to?

Fuel filler neck hose.
Fuel filler hose - tank end. Either Long with bend or Short tube 60 mm internal.
What sort of clips/clamps are needed? not jubilee clips.
Check Steel fuel pipe and grommet where it goes through the tinware

Are there any other bits that should be looked at or replaced please.

Thanks in advance

 

Baysearcher, thanks so much you are like a one man question answering machine!

People kept mentioning 7mm in other posts so I've been confused.

I'll get some 5.6mm ordered now and see what condition the fuel filler hose (tank end) is before spending £56 on a short bit of pipe!

 

type 4 have 3 different sizes of hose 5.6/7/9.5 if I recall.

 

most of the suppliers list 7mm for breather pipes, I bought some and found I could push it on.....and slide it off far too easily for my liking

so I got some 6mm hose R9 rated locally for a fraction of the price ......it was a nice tight fit and I had to warm it up in a cup of hot water to soften it a bit to get it on the breather pipes......once cooled it wasnt going anywhere

 

^this. At a pinch you can use 7mm for breathers, but it tends to slide off.

 

Jubilee clips are ok for large diameters such as the filler pipe. Fuel tank breathers go to the weird cigar cases (condensers) in the air intake vents.

 

Jubilee clips are ok for large diameters such as the filler pipe. Fuel tank breathers go to the weird cigar cases (condensers) in the air intake vents.