I've done L'Art de Choix, a few years ago now but here's what I remember: Burly, undercutty bouldery start on big holds through roof, then a good rest, then the crux boulder problem leaving the rest getting over the overlap and getting established on the vertical wall above. Small undercuts and shallow pockets and/or crimps I think, but short lived. Easy romp up a big flake to finish. Did it in July or August when it was about 30 degrees and humid.
Not done any of the other harder routes at Chaulet.
Actinidas is better for harder routes in summer as it gets the shade.