I bloody love a cushion! On the bed, the lounge, an occasional chair, if you can sit or lay on it, it deserves a cushion or 2 or 9 as i have counted on my own bed (including pillows) but how many is too many?? hmm..
According to an article on domain.com.au a bed looks better a little untidy and fewer pillows and cushions, i do agree with an untidy make but and however i'd have more trouble choosing which cushions to put on the bed then taking them all off the bed before i go to sleep.
they say for a queen : Two Euros, two to four standard pillows and a MAXIMUM of 3 decorative cushions.. so i guess that adds up to 9 but can you trade out a couple of pillows for more cushions, i vote YES
Now for the arrangement and how to choose, i know some people that cant get the concept of cushions that aren't identical and all in specific places on their bed or lounge, i am more of a grab an "out there" design and work backwards, then your options are endless, i think you just need to close your eyes and commit, well maybe not close your eyes completely, you still want your bed to look super cool!!
As for the size of the cushions i say all different shapes and sizes, all different textures are also great
at the end of the day if you love the way your bed looks, that's all that matters, everyone's style is different and that's fabulous because who else are we going to get ideas from if our styles were all the same!
Love and Peace, T x