P98BK is a great strain, one of my favs. I had quite the affair with her for many years.
She is a shorter plant with minimal stretch at the flip. Multiple toppings during veg will benefit greatly with yeild. She is also a heavy feeder, eating mg like mad.
I fed heavily with botanicares sweet raw for my extra mg when running P98BK, and it also has a good amount of sulpher, which is great for bulking.
It is a little pricey, but you can use Advanced Bud Candy for mg instead,and it is cheaper and u use less, but it has less mg and little sulpher.
Temps are critical also with her. Too cold, she won't yeild much, too warm, the herb is very dark. The best is running about 78 degrees the first 4 weeks of flower then drop temps a degree or 2 every week, ending at around 70-72 with lights on, and a good 65-68 lights off and she will color up.
Good luck