ballasting with integral tanks

I remember having once seen on 'Soaring' an article
about a clever (albeit complicate) ballasting system
designed for an LS6, where water came from the mains
supply, but with a vertical spill pipe of a precise
length inserted between the supply and the glider,
to avoid exceedingly high pressure and wing shell bursting.
Anyone using this system for integral tanks with bottom
filling (LS8 style)? What's the advisable spill pipe
height for a quick but safe fill?
Thanks in advance,
cheers
Flavio