some general pointers.
the slaan general is mandatory. the entire army is balanced around it, and you should be banking all of his spellcasts as summoning points with few rare exceptions
engine of the gods is very solid, and further bolsters the armies strengths, take 1.
bastillidons are very very good, and the thunderquake host is a very strong way to run them.
you will need skinks. often, drowning the enemy in summoned skinks is a strong strategy, and you will need a lot of skink models to make use of this.
summoning in artillery lizards can be strong.
attached is a pic of the top seraphon list from adepticon, i dont have anything more recent, but i think this took 1st place at that event, and it was only a month or two ago.