I had a 189/4 son once. He was a fantastic bull. I never had any calving issues out of brahman cows. My simmental cows were a different ball game. Lost a few and pulled a few calves, lost 1 cow and 1 heifer. A person should use caution when breeding a brahman bull over english or continental cows. I think gestation period is longer on brahman.
Our 189 son was a farm favorite. Great disposition, easy loading, and sired great uddered females. Your calves should grow like weeds, but could be spunky, ( I like charolais have several, but no charbray). We bought our bull at 8 years old and sold him back to the original owner at about 11.
Do you plan to sell the calves for beef or retain some heifers? A hereford would probably work well over that cross.