I did my IR whilst still holding down a full time job but it was so tough.
Took me about 10 weeks and apart from work everything else was on hold.
I work shifts so that helped a bit. I usually do 2 late starts a week so used to do 2-3 hours sim in the morning on those days go in to work looking like a zombie. Weekends was spent at the airfield back seating and catching up with other students and the other 3 days was reading my notes. I gave my partner 1 or 2 nights a week just us.