Being that you actually seem to know what you are doing with diet, I will cut all the BS that I normally give people who are just starting out. If you havent started yet, this is where a supplement can help. Look at Dexaprine+TT-33. I have used this multiple times for contests and it works great.
Also if you do HIIT, I would recommend doing it on Leg Day after training ONLY! This way you give your legs a good thrashing and that is the end of it. Rest of the time, do some LISS. NEVER MISS, and it shouldnt be long till you hit your goal.