I always used a wet mane and fine tooth comb to keep the loose hair out of the way. Never learned how to use a clip. The only 2 braiders I know who use clips started braiding in the 70s or 80s.
If I had put in 20 or less braids, I think trainers/owners nowadays would be quite displeased – and rightly so, given the cost of them. Like, if today a horse had braids like this grey horse, or this top photo, I don’t think it would go over well. For $80-100, I’d expect braids to look like this. Or these wall-of-braids.
Older braiders reminisce about the old days too, when they were getting 20ish braids or less, and braiding horses something like 20 minutes, for like $15-20 (or less? google’s inflation calculator tells me that $20 in 1975 is $91 in 2017?) for the mane and tail. And they had long bridle paths, too, I hear, and didn’t braid the last inches of wither hair, and that tbs often had thinner manes than wbs, and no one had fake tails, and sometimes they got yarn that matched the rider’s shirt colors. These braiders also have changed their braiding style and prices with the times, or got out of braiding.