I waited until 6 months when DS was well and truely ready. I only gave him fruit and veges the first few weeks and he flat out refused rice cereal.

I give DS some finger food but his strike rate isn't great and not too much actually goes in so I try to do a bit of both. So for instance tonight I gave him

Chicken breast (I minced it at home)
Mushroom
Zucchini
Brocolli
Sweet potato
Pasta

I chopped it all up but didn't puree it, he still needed to chew to get it down and then I gave him some cooked pumpkin to self eat.

He is loving his food, I too worry about quantities but I am trying to take his lead. I agree, as long as they are still having enough milk it shouldn't be a problem. DS still feeds at least 6 times in 24 hours including overnight but I'm hoping he drops one feed soon.