Best advice I can offer if you're having to Di and you're using the venues sound guy (or someone front outside the band) is to completely trust the sound guy to the point you almost don't care.
The sound guy will know his desk and pa better than anyone, and the room if he works there regularly so he'll get the best sound for the band from where the audience are. To do that give him the absolute best, clean non eqd sound you can.
You need 100% trust though. There's nothing worse than worrying about how you sound out front when you're playing, and nothing worse for a sound guy than a band member trying to do his job for him from a position where they can't even hear what it sounds like in the mix.
If the sound guy is someone in the band, then same rules apply, but you can have some input into how it sounds, but be prepared to sculpt a new sound.
In short, if you really need Diing to PA, your on sound stage will not always/ever equate to a good bass sound at the back of the room.
Only my opinion though, other people's experience may be different.