Hi, I just wanted to chime in and say that you don't really need to do much (if any) ab work to have visible abs. I've been lifting for just over 2 years, 1.5 of which was powerlifting focused and only 6ish months of bodybuilding. In that time I may have spent a total of 20 minutes doing ab exercises. I'm no Channing Tatum by any stretch of the imagination, but whenever I lose a bit of weight they get really visible.
I'm on my lunch break at work, but I took a couple quick pictures on a bloated stomach to prove my point.
I'm no expert, but my ab visibility comes and goes with the amount of fat covering them. I haven't done a single crunch or plank (or even cardio) in 2016 and have more visible abs than everyone I see at the gym doing ab workouts.
If you want to see them faster, I would spend that few minutes you do on abs doing pullups instead. Big lats look great on both males and females, and more muscle = faster metabolism.
If you can increase your metabolism by adding muscle and have your body burn an extra, say, 200 calories per day, that means that you can expect to lose an extra lb of fat every 2 weeks or so (if it takes ~3500 calories to burn a lb of fat) literally by just existing, even if you miss the gym a few times.
A lot of people think how many calories per gym session you burn is most important, but that's not very sustainable. Being more muscular is like investments. You may not see the quick results, but those daily required calories compound and, over time, just existing will burn the same amount of calories as a half hour on the spin bike + planks.
At least, that's what I've experienced. I hope my long post was helpful:) Good luck!