i have been doing dumbell floor press as a main movement for chest. i barbell floor pressed a few times but couldnt keep the tension on my chest. it really seems to get the shoulders out of it but my triceps took most of the work. but for some reason i get an intense contraction with dumbbell floor press and flies. i have been focusing on progressing those for the most part and adding slow negative dips and incline (feet raised) pushups at the end of my chest portion of push day. i was always an advocate of full range of motion but since discovering floor press only a month ago my chest (especially upper chest) is noticeably more dense.
If its working just go for it. You found a movement the really does what you want, don't question it. Re range of movement you can always go back to full range of motion in a couple of months, or add a full range movement later in the workout.