V.T.
i have the saftey first potty chair from walmart that works great. i like it. i have seen a chair that i don't like. it has a soft cushin for a seat but there are too many parts and you basically have to take it apart to throw out the pee. we also have a potty ring that we keep in the downstairs bathroom. as for public you teach them to put their hands down on the potty and hold themselves up so that they don't fall in. lol. at first you will have to help hold them but i was surprised at how quickly my 3 year old learned to do it herself. now we don't use any sort of potty aid.
since your daughter is just 16 months old i would keep the potty in the bathroom and start to introduce it to her. a good way to start is to have her sit on the potty right before bathtime.