fuel tank drain holes

[tiggersmini]

Just been looking on the vosa guide, it says you need drain holes but not what size, does anyone have an idea or have put drain holes in. I was thinking of 2 x 10mm holes with some pipe/tube hanging under the floor pan so the fuel does not run along the bottom of the floor pan, in theory it should drip straight onto the floor.
Boyd

 

[Phaeton]

It isn't very clear, just says something along the lines of making sure the fuel cannot get into the passenger compartment. I would have thought the more the merrier.

Alan...