Whatever you use, it takes quite a lot of liquid to make cereal thin enough for a baby who is new to food eat it and like it.
You can always add both breastmilk and water, which is what I did for DD#1
I can only pump 3-4 ounces of milk a day and if I feed 2 cereal meals I'd use 2 oz of breastmilk to a Tbsp or so of rice cereal and then add water to thin to the desired consistency.
A few weeks ago (at 4 month mark) my mother would not stop bitching about trying LO on cereal...
so I gave in and we made some up.
She liked the taste, but it didn't settle well in her tummy that night. She's still not to a point to be able to move her own burps very well, and having that 'thick' food down there just makes her gassy and uncomfortable. Plus eating and swallowing solids makes her swallow a lot more air.
So needless to say, my mother has finally stopped bitching after that.
lol
Anyway, for one Tbsp of dry cereal, we added just about 2 ounces of liquid to make it quite thin for her. When she's ready I would guess in another 4-6 weeks, that will be about the perfect amount for a meal, with a Tbsp or so of pureed veggies or fruits.
I also tried her with orange veggies to see what she'd do, and she very much liked the sweet potatoes, and her tummy liked them a lot more too.
That said, we're still waiting to fully integrate solids until the 6 month time frame. Not only because her digestive system isn't mature, but for her ability to remove air ... burp
Hope that helps?