The short answer is, I don't really know.  For the most part when you are talking about red/black hair color it is a case of simple dominance on a genetic level.  I am aware of the variation in color and combination between the two, but for the sake of discussion we will say that it is simple dominance.  Since black is the dominant gene, if an animal has one copy of the black gene it will express the black hair color.  It takes two copies of the red gene in order to express the red hair coat.  What I don't really know is how the white color figures in.  I don't know if you will be seeing some solids or not.  However, the most likely answer would be that you should have about 75% of the herd expressing some form of red baldy.  Unless you managed to get a hold of a black hereford bull and used him to produce the black baldy.  Then you would be much more likely to have every calf express black color.

If you are interested in maximizing heterosis though, this is not the way to do it.  As has been stated, the maximum amount of heterosis will be in the F1 animal.  So if you took a black or red baldy, stipulating that this animal was bred using angus and hereford as your parents, and then crossed it back on angus cattle you went from a 50-50 split of breed representation to a 75-25 favoring the angus breed.  Probably wouldn't be anything wrong with the animal, but that is one of those crosses that I am not sure makes a lot of sense from the genetic standpoint, or the production standpoint. 

As has been alluded to here, when you are planning your crossbreeding, you need to figure out what you are trying to achieve before you start.  If you hear people talking about crossbreeding and decide that you want to get in the game as well and just go pick up a different breed of bull to put on your cows, you will get heterosis, but now what do you do with it?  If you used Hereford on angus you have got a pretty good maternal cow, but not necessarily the most growth.  If you go get a Charolais bull and put on your cows, now you have got lots of growth, but you probably don't really want to keep the heifers.  So you need to be planning several years out as to how it will affect your herd.  If you always purchase your replacements, then you are setup perfectly for a terminal cross.  Go buy some charolais bulls and you will always have good weaning weights.  If you want to raise your own replacements, then you need to recognize that you are going to have to shift focus a little.  You will probably have to give up a certain degree of growth in trying to get the best female for your envirnoment. 

We raise all of our own replacements so we look first at frame and mature weight and then at maternal traits, milk, CE and stayability before we start looking at carcass traits.  I know that I am not ever going to have the heaviest weaning calves, but I am fine with that.  I want to produce as balanced of a multipurpose animal as I can.  We have tried several crosses and have yet to settle on one that we like as well as straight red angus.  The 3/4 RA 1/4 Saler was a tremendous maternal animal, but you couldn't build fences high enough that they wouldn't try to jump them, and if they couldn't jump them they would go through them.  As soon as we put south devon into our herd we lost our hind quarter and our growth.  Those things are hardly anything more than a big eared, solid colored gurnsey that doesn't milk.  We tried gelbvieh and didn't like the temperment or the body style.  Right now we are trying non-spotter, non-diluter red simmental.  We are cautiously optomistic about that cross.  It is looking like we can pick up some growth without losing the maternal animal.  We are keeping a real sharp eye on disposition though as I think that might be a weak point.  What we are trying to do is get an animal that looks and acts as much like an RA as we can but has more growth than we can get with straight bred animals.  Since we are commercial we still make our money by selling pounds.