How do I convert a weight of dried chick peas to volume of cooked?
There is no exact conversion because there are so many different varieties of chickpeas or any bean types for that matter

Their water absorption rate and amount is effected by many things including how they have been stored, have they been heat treated on import, and what time of year they where grown!

My rough rule of thumb for beans in general is 2.5 ±.5 times the volume and 2 ±.5 the weight after an overnight soak

With our local chickpeas it's 2.2 times the weight after 10 hours at 20°C (on the bench)

200g should be around 440g of soaked chickpeas. 1 cup of chickpeas is around 240g, so just shy of two cups of soaked chickpeas should do it