Hmmm... I need some more info from you. Do you bring your own micpre's/mixer? Otherwise a splitter won't take you that far. But you already know that I guess.
So, there's a few ways. The ideal thing would be using a splitter ofcourse. That way you can work independently of the FOH mixer.
Another way is using directs outs from his board. Check the manual of the board if it has direct outs, and where they are located in the channel strip. Pre fader/post/... You really don't want them to be post anything except for the micpre. EQ could be ok, but there's nothing that guy can do with his equipement that you can't do at home. Plus, that guy is EQing to make it sound in that place, on that soundsystem. So he is really making it work for the respons of the room and system there, and not making it sound good in general, which is what you are aiming at in the studio.
Also, I don't think you want too many inserts in between. The comps and gates for a live environment are not always set that precisely, and I don't think you want them on track anyhow.
Then there's the option of using the inserts as direct outs. This is about the same as just using direct outs, but on a different place in the channel strip. Mostly preEQ and prefader. Check the manual of the board on this. Also, you gotta check that on-click thing, it doesn't work on all boards! (input/output, tip/ring are sometimes reversed on the inserts!)
Also, if the FOH mixer wants to use inserts, you got kindof a problem. Or you could make special Y cables for that?
You could also use the micpre's of your board, and feed him the inserts of your board, then record the direct outs of your board. This way you have control of the gain on the micpres!
And ofcourse you can use any combination here. Use inserts wherever he doesn't need them, and other things like special cables if he needs them....
Be carefull if he has control over the gain settings. Not all FOH mixers use the gain to get the signal at optimum level like you want as input for your recorder. Some will make a balance using the gains, and the faders will be almost alligned! You don't wanna go there...
I've also seen guys that have some channels clipping deliberately!
So, be carefull, talk it all over with the FOH mixer there, ask if he maybe got some ideas.... It will be more work for him too, so you really want the guy on your side!