I am surprised at the problem with the petrol tank mounting. Son Rob has changed from a centre bolt tank to a fluted type without problems on his VH. Using the fluted tank, there is always the issue of tank rubber thicknesses to deal with and this can be far from straightforward.
36 4G, 37 VH, 54 KH(A), 75 Healey 1000/4, 52/53 ex ISDT KHA (project).
Former Machine Registrar & Archivist, General Secretary and Single Spares Organiser (over a 25 year period).
Now Archivist once more - but not Machine Registrar.