The correct amount of ptfe or 55 thread, will allow you to position the bent irons in whatever direction you need.
It comes with practice and, with all the different valves and threads on the market, even us traders need to redo one sometimes to get it feeling "just right".
If in any doubt, then the straight iron and street elbow solution is always a work around but sometimes you just don't have the space availvable, due to studs etc.
The key is to connect it all up and pressurise the valve in order to test the inlet and outlet connections of the valve... Use various caps/stop ends on the outlets and leave the whole lot under pressure until the close up and tiling is finished.