Thats not true! If you listen to what you recorded, after you finish the first verse, theres still loads of time for you to continue rapping but you don't! There was about 6 bars left. You filled it with words like "something stressed". I personally think it would have been better if you would have continued rapping. I'm not disputing the fact that other rappers have different length verses but like I said .
Adlibs are easy. You don't have to do anything special with the programme you use to do it. All you do is rap over the top of your main vocals, emphasizing certain words you want to stand out. When you have finished doing this, you simply turn the adlibs down a bit to create a more harmonised sound. Its as easy as that.
Trust me....if you do everything I've told you, your songs will sound better. At the moment, they seem rushed and like your always out of breath. Take some time and pride in your creative work and you'll appreiate it alot more.