Fuel system overhaul

So my 85 xmas cabrio  seems to have  been bodged over the years so it leaks fuel & stinks ( but still runs fine) 
My plan is to replace the whole lot.
Tank, pump, accumulator, lines everything .
1. How to get tank out?
2. Need to know sizes of pipes etc 
Ive only got use of a rank for a day 
Can anyone confirm the sizes of pipes from swirl pot to pump as heritage want nearly £100 for a metal pipe & piece of tube which seems excessive as at the moment it looks like mine uses a hosepipe . I hear 8mm 10mm & 12mm ? 
Ive got a spare accumulator pump bracket & pump ( although its a smaller diameter housing?) 
And am replacing main lines with flexi


Anyone does this can help or have bits they can measure