Golden ages are best used when you aren't Spiritual and want to change religion and many civics in a short time.
The Illians and the Calabims world spell are best used early.
For the Calabims, grow to 3, use the spell, and you'll hit pop 5 (which is usually the limit that early) and everybody else will be at 1 (depending on difficulty and civilization, they might be at 2).
For the Illians I would scout the area, to see if I wanted to rush someone, then trigger the static if I did. But at least grow to 2, you can keep the enemy's capital. Alternatively trigger it when you build Samhain, frostlings everywhere and no building is evil.
The Malakim world spell is best used after you have expanded and settled in a religion. Obviously. You can REX and then use this spell to take out the nearest foe. Pretty much the same with the Doviello spell.