Doubles - serve down the middle unless you have a really good out wide serve. Serving down the middle minimizes the angles someone can shoot for, so unless they're really good with nailing low % returns down the line from the middle position of the service landing, you're almost always assured of a cross-court return or a popup over your partner.
Bottom line is this, if the guy isn't going to poach when he says he's going to call for a poach, then it's no different then him waiting to see what the return is and reacting to it, just like you should be serving and watching his reaction to judge what you should be doing in case you need to switch.
That said, it sounds to me like you're not to the playing level where you like having the net partner call your serves as what you wrote shows that it puts too much pressure on you and you can't serve in the right spots or you double-fault. No problem, just be sure to tell your partners that want to play that game that you cannot because you're not confident on serve placement. Until you get to the point where your serve can reliably force errors on both your first and second serves from same level ranked opponents, you have no business letting your net partner call the shots because what that says is that your serve is weak enough that he/she will get eaten up alive trying to attack the return of serve. Until your serve becomes a weapon, work more on starting the point out and then playing it out instead of trying to start and finish it by attacking the return of serve. You cannot attack the return of serve if the serve is no good because the return will usually be a punishing one.