There is a chart that Spanky posts often which he calls a “feeding cheat sheet”. In the meantime, I don’t think the feeding routine is different between Fox squirrels and grays. The amount is still based on 5-7% of their weight at each feeding. At 3 weeks old they should eat about 6 times a day and the night feeding can be discontinued.
Without knowing the weight of your babies I can’t tell you if the 3ml is enough or too much per feeding.
I found the cheat sheet!!!. Here’s the link
https://thesquirrelboard.com/forums/...2&d=1677673701
And here’s another helpful bit of info.
https://thesquirrelboard.com/forums/...4&d=1677673725