Yes, BS...you do get MORE flank when cattle get fatter/more mature, but there are also cattle that are deeper middled and those that are more shallow... I think what flcc is looking for is a bull that produces maternal power in terms of broody females that have some middle and depth.
I manage some Angus cows and have used Rendition. Those calves are not bad. My best calves, though, are out of PRS Blazin' Hot, another baldy bull that is working really well on Angus females. The calves come small and grow. They're loose made and sound structured. And the heifers are deep sided and easy doing. I'll wean the first calves by him in April. I'll try to have some photos to post...I'm pretty proud of em. Compared to Rendition, Blazin Hot is homozygous black (Rendition is red gene carrier) and he has better EPDs. I particularly like his API of $136 which is in the top 4% of the breed. There aren't many good baldy bulls that can match his numbers, and even fewer that are homozygous black. And I've looked for em!
Anther bull I would consider if you don't care about the blaze/baldy thing is Ellingson Legacy M229 aka "Olie" at ABS. Olie is more known for adding length and muscle, but I haven't seen him take away on depth either. He works really well on Angus cows and makes nice half blood females. His sire, Legacy, is one of the best cow-making Simmental bulls around, and I think Olie will follow in his footsteps. And the Olie calves may be a little flashier than the Blazin Hots, but the first Blazin Hot calves are not ugly, either. I will tell you this...Olie's picture in the ABS catalog is not pretty. I wouldn't judge him based on that. Instead, ask people who have seen the calves...the ones I've seen have been sound structured, moderate sized, stylish and just pretty complete.
If you do choose a blaze faced bull, understand that most of these bulls will throw blaze faces / baldies about 50% of the time. So don't be disappointed if you breed for a baldy and don't get one. If you wanna try to get a blaze faced calf, use the best baldy bull you can find and hope for the best. If you do get it, it's a bonus. I wouldn't use a bull JUST because he's a baldy because your chances at getting the white face aren't any better than getting a solid black calf.