If I am making pie dough, for instance, is there a reason to prefer doing things in batches, besides it being more manageable for my tools/hands? This would help answer this question (two good answers which differ on this point). Obviously, you want to divide the bulk into portions at the end, i.e. for the pies. But why sooner?  I always figured that following the directions all-at-once until the end ensured that the final product, by whatever multiplier, is consistent throughout.  I'm assuming that when baking in large quantities, we are measuring by weight, not volume, so accuracy shouldn't be an issue. 
If you have a gas range, just fire up a burner. Make sure to have some tongs ready if you can't rest the pepper at a good height above the flame. (You'll probably want them to turn the pepper anyways.)  Once sufficiently blackened (and not on fire mind you) toss in a paper bag and close it. Let it rest and the residual heat inside the pepper will continue to steam it from the inside out.  Once cooled, remove the skin.  Feel free to use water to cool or help remove the skin, but you may wash away some flavorful oils.  I prefer this method as it lets me keep an eye on the pepper the whole time instead of having to peek at a hidden broiler. Plus, you can make sure you get an even roast. 