In reply to LeeWood:
There is a lot to go at around those grades in the shade, the Tarragona guide is selective so probably omits a lot of it.
I've nearly finished updating the Margalef crag page Margalef - Zona del Panta North with all the climbs from the latest guide book so it's a good place to look. All sectors are accurately placed on the map and i've tried to indicate dcrag direction or times that the crag is in sun in the description.
It's a bit of a beast to navigate as it's all on one page but have a look at Can Pesafigues, Can Mansettes (morning/early p.m), sector Reggae, chorreras, Can regino, bloc del porc.
A lot of the 'sunny' crags can also be climbed early morning or on a cloudy day, opening up more options like Cami de l'ermita, el toboggan, punta espadelles.
Because of the style of the rock, many routes start with a hard or steep pull from the floor with easier climbing above, so if your son is happy to swallow his pride and get a leg up over the first hard moves then even more routes become accessible.