I don't braid at events, but I posted a thread in the dressage forum about braiding a thick mane. A lot of people suggested button braids. For a thick mane it works better than hunter braids but in your case it would simply mean you don't have to make as many.
If you have a nice, easy mane on a horse whose not a rubber, you can just use bands. Braid down, slap a band on, fold in half once, slap a band on, then fold over once more, wrap the band around and your done, usually in about 20 minutes!
If you are not so lucky and have a thick, hard-to-manage mane on a horse who is a certified braid killer like me, then you'll probably have to sew them in with a needle and thread. Once you get good at that, it'll only take 30-40 minutes depending on how many braids you put in although there's a small learning curve with this method. But if you do it right, nothing short of a nuclear explosion will make those braids fall out!
If you have a longer mane you can also do what some people call "eventing knots." Those will come out looking like buttons. You braid down with the yarn as if you were doing a hunter braid, then literally tie the braid around itself into a knot. Then you simply pull it up with a pullthrough and secure it.
Here is how I braid. It takes me about 15 minutes with rubberbands or 25 with waxed thread (due to rethreading) and puts about 9 braids in the average mane (with 10 being the forelock).
Take one of those metal pulling combs and section out the mane using the width as your template. Rubberband each section. Spray each section with QuicBraid or spray gel and braid down, looping the end up when you do the band around the last 2 or 3 times.
To put them up with rubberbands, fold the braid in half then roll tightly and secure with 2 rubberbands.
To put them up with waxed thread, have your needle threaded to about half an arms length and knotted at the end. Put the need through the loop at the bottom of the braid and then back through the loop of thread. This will tie the thread in. Sew up through the top of the braid at the base of the neck and then back down. Roll the half braid up tightly to the neck and sew back and forth through the middle and bottom of the braid roll about 4 times. Cut thread.
I've braided at three days this way, and it works really well! The thread makes them sit really nice, and isn't that hard to do. Rubberbands are quicker though!
No hour of life is wasted that is spent in the saddle. ~Winston Churchill
Button braids, as shown in this video from EN. I vary the number of braids depending on how much time I have, or how important the event is. For the big shows and 3 days, I'll take my time and get about 20 small, neat buttons in about 40 minutes. For an 8am novice ride time, I'll throw in 12 big chunky ones in 20min.
I love the security of sewn-in braids...I've never had one come out, despite some serious rubbing. If I have to braid the night before, I can just brush the shavings and dust right out. The braids look just as good several hours later for show jumping, if left in after dressage.
I really enjoy braiding. I like the immediate "face lift" it gives a horse, showing off a well-muscled neck and topline. It's been a nice bonding time for my mare and I over the years, I can't begin to add up the hours I've spent bent over her neck braiding. And she's learned to enjoy it, she'll stand halterless, untied, in the stall, perfectly still until I finish...it almost puts her in a trance. It allows me to focus on what I need to do for the weekend, plan my warmup, review my test, etc.
When I braid I do yarn... and yes I do hunter style braids but I DO NOT to 500 of them lol. I probably do something like 24.. takes me 30 minutes at most. My button braids always look like crap so I go with what I can do that looks best. I also find the yarn so much easier to take out than the waxed thread.
The Dutton way of doing it interesting though (and they use yarn!!)... so I may have to try it!!
Oh my gosh, the video from EN looks like it would take forever. I use the Dutton way of braiding. 20 minutes, tops.
Ditto. I've used the Dutton way the past few events I've been to and it is very simple and looks really nice - plus it actually works better with a slightly longer/thicker mane (as compared to hunter braids). My last event, I received several compliments on how lovely my braids were.
I also use the 'Dutton way' and can braid up in just over twenty minutes with 15 braids. The princess has a long, delicate neck so I don't usually go too big with braids, they look funny on her. I always get complements on how they come out. It does take a slightly longer mane (less pulling, yay!) so not recommended for a really short mane. I've found that they're not as stable as the sewn in button braids, so for special occasions or if she'll need to wear the braids for awhile I sew them in with waxed thread.