Ed, welcome. The first suggestion would be yes, if possible move your listening position at least 4' from the back wall so that the back surround speakers have some room to actually create a recognizable back effect. With back speakers being present in a 7.1 setup the side surrounds don't need to be placed a little farther back to add some back effect, so they they should be directly to the side.
As to the type of surrounds, at least the side surrounds should be QSs to give a wide spread of general ambience effects. If W22s are also to be used, they would be more beneficial in back to allow a little more specific placement of movie effects which are meant to be placed directly in the rear. This isn't critical, and QSs all around are certainly a good option.
