3 seconds between rounds. That should be "easy enough" right?
. I suspect you'll have to practice, but as long as double taps at 25 yards isn't the drill, I suspect you'll do fairly well.
Definitely want sights to help though. I'm not painting the rears, just the front. I've learned from a friend that some instructors discourage the rear sights to the point of "magic markering" them out...students suddenly become great shots. Front sight picture is the most important IMO. Every time I've tried to NOT look at the rear 2 sights (3 dot) and concentrate on front sights, my combat shooting improves immensely.
Of course, there is a line of thought to not use sights at all.