Interesting situation - either light "comes up short" in one dimension. Your tent is about 2.5' x 4' so the SP 3000 will do a good job because it's designed for a 2' x 4' tent but you're not getting much light across the front (or back) of the grow. The FC 3000 is for a 3' x 3' space so you'll have good light front to back you're losing coverage across the width of the tent.
To my way of thinking, given that you have a rectangular tent, I'd get a light designed for that form factor; that is, the SP 3000.
Full disclosure - I have an SP 3000 and I think it's a good product.