Waste tank pick up /dip pipe query

[DanTribe]

I'm just finishing installing a waste holding tank and only have the discharge pipes to fit.
How far off the tank bottom should they be?
Too high and stuff will be left behind, too close and likely to clog. Should they be cut on the splay?
I can't find any info from the suppliers [Vetus] or from Googling.

 

[tillergirl]

If you pm me an email address I can send you a copy of the drawings of my recently purchased bespoke tank from a well known supplier. Dip pipe is cut at 45% at the bottom and just off the bottom of the tank.