Oh, the Focal Shape 40s are a solid choice! I've been using them for over a year in my setup. What I really like about them is the clarity they bring to the mid and high frequencies—quite crisp and detailed, especially for vocals and string instruments.
For positioning, invent sure they're at ear level and try to keep them away from walls to minimize bass reflections. Also, play around with the tuning options on the back; it can really help adapt the sound to your room's acoustics.
Experiment a bit with placement and settings, and you'll likely find that sweet spot for your mixes! Enjoy those speakers; they're fantastic once dialed in right.