If the age of the kittens are 5 and 8 weeks old they will be sosialized fairly quick,after all they have lived with people from birth so they will be housewarm in less than a month.(this is if the age given in the edited question is the correct one).

If the age given in the original question is the correct one 5 and 8 months old,it will take a lot longer before the cats are fully sosialized.

Young feral cats will not have had the inter action with people that kittens born in a  household will have,the older the feral cats are the harder it will be to sosialize them.

A feral cat will often hide during the day and come out to eat at night when people sleep,It can often take a month before the cat comes out of hiding during the day it is important to try to inter act with the cat at this time.

When the cat comes out during the day you can try to play with the cat using a stick toy,this is to slowly build trust and you can expect a few setbacks during this time,let the cat escape and do not follow it but try to engage in play later.

When the cat starts to relax and play it will use some energy in a no stress situation,this is the time for you and the cat to start to get closer to each other.

By what you say in your question it sounds to me like you and the cats are well on your way to get to know each other,whitin a couple of weeks you and the cats will have made massive progress.