hi hun, I used the cow and gate baby rice from when Oran was 12 weeks as he was on hungry baby and still waking a few times in the night for feeds the monkey, he was fine with it. I started of with a table spoon (not heaped) and mixed it with warm formula till I got the consistency I wanted, evry 3-4 days I just made it a tiny bit thicker, and added a bit more rice till he was 4 months and could be weaned properly!
you can do the rice with form/breast milk or warm water. What I did was start at his mid morning feed, so around 11am, give him the rice then let him take whatever milk he needed to fill up - usually was abut 3 more oz (he used to have 7-8 at that feed) then after a week I gave him it at the 11am and tea time feed (5-6pm) and again let him top up with milk. then gave him his normal bedtime milk and he pretty much slept from 8pm-5am without wanting a feed from then. The other thing you could do which I did on occasion is instead of giving it at tea time, get an old teat and pearce it with a squerand mix some in with his bedtime milk to make a thick constincey but so it still comes out the teat (trial an error, start off small and test and add lol) but you can only do this if not BF his bed time feed, this might fill him up for the night also.
hope this helped chicken