I taught these harmonies at West Bridgford Liberty Singers rehearsal this week. The Yellows and Greens (altos) make up at least half of the people singing. The blue section (tenor/bass) makes up for about 25% and then there are the reds (sopranos) which make up another 25%. There are then, what I call the hyper reds! These are around 6 or 7 ladies who take the highest part of all.
Red Harmony

 
Hyper Red Harmony

 
Yellow/Green Harmony

 
Blue Harmony

 
All Together!

 
Have a listen and see what you think. Can you hear your own part amongst the 4 parts? Can you sing along with it? Can you change parts!!!???