Optimal Speaker Placement

I would like to know others thoughts on optimal distance between speakers as well as distance to listening position. I currently have my speakers 9' apart and they are 10' from the listening position. I am fortunate to have a large room and do not have any sidewall or rear wall issues. I am using Vienna Acoustics Mahler speakers which are full range speakers that project a large soundstage. My speaker cables are short and with my current equipment positioning I do not have the ability to test putting them closer without changes in cabling. The speakers do sound good as is but my concern is that they may be too far apart and I am missing some focus. Any thoughts on this subject would be appreciated.