we moved to bottles at about 11 months with ds1. I was pregnant with ds2 so had no choice, my iron plummeted.
He went straight to milk (didnt like formula) and initially didnt like the bottle. He would drink milk from a sippy but I wanted to try a bottle at bedtime. I put jam on the bottle teat for about 3-4 days... and "tricked" him into drinking from it. At the beginnig I would try the bottle first at night, without jam first, if no luck then try with jam, (just a bit to make the teat taste sweet).. I would limit three attempts with the bottle and then wait 10mins before I offered BF. ( Ididnt want him to associate failed bottle with BF success). It took 3-4 days to accept the bottle instead of bf. Once the bottle was established I stopped BF completely. I actually found that the bottle at night filled him up more ?!? and it wasnt long before he stopped wanting his early AM feed anyway. I think we probably had a few days / weeks with earlier than normal starts cause I refused to give that feed and he quickly readjusted (he is/was an angel bub though).
I loved the freedom on not having the early am bf but did miss it initially, it was such a nice quite time together.
ds1 is now 23mo. He kept his evening bottle til about 20mo. He used to have it about 30mins after dinner (and only about 120ml - 180ml depending on how successful dinner was). I didnt want to introduce a prop.
I replaced it with water at 20mo and he didnt want it anymore. I mistakingly introduced the bottle at a NF when on holiday at about 12mos... dont do that!! He really didnt need it but I felt like I had to give him something. Again it didnt take long, once I'd made up mind, to drop that occasional NF.
He is now a very independant sleeper that sleeps 11 -12hrs with no fight. NW are VERY rare and purely a result of something being wrong, ie bad dream, teeth, temperature etc.
HTH
Gem