Totally my colours, so I can see why you like it.
Agree ... don't cut it .... and use it for a backing!!!
Without matching the pattern, it would give you a backing approx. 54"x80"
But I would definitely match the print, to keep it looking awesome.
Once you know your backing size, then you can decide on your front requirements!
I would use the offcuts to make a top with the coordinating fabrics you already have.
Or even, do the top without them ... kind of like a two for one deal ... reversible!