You might get better response from the AC Cichlid forum since you are asking a cichlid question, but I vote for the angel growing faster, unless the angel ends up as oscar chow
I am not sure how fast the angel grows, but you can expect the oscar to grow 1" per month, so I doubt the angel will out grow him unless it reaches full size in 5 months.
As far as height goes, not overall water displacement or length, the Angel should grow faster. At temps of 84 with clean water and lots of food, they do grow VERY rapidly.