I'm 5% 5'9 and my waist is 29 inches, if my waist got any smaller I would loose ab size and you will look less ripped. It's not that hard to get down to 5% and maintain, just remember that after you reach 5% change your whole diet and trainning. Since you don't want to loose any more fat you just want to maintain. My diet now is no less than 200-400grms of carbs a day. I don't deprive my self of anything, cookies, pizzza ect and I still maintain 5-6%. It's also all the high intesity stuff I do, you are doing the right thing by spriting. This will make your body a fat burning machine in time to come. It's actually quite remarkable how explosive movements work, you will understand once you achive 5% how easy it was. If I may give you a bit of advice, low carb is good but don't forget to carb up. Carbs are actually not as bad as you think, I find the MOST important thing to loose fat is not low carb but calorie restriction and calorie manipulation, confusing your body works great for burning fat.