I agree with getting a blazer instead of a western shirt. It will look much more polished, and from someone with some belly bulge (im pregnant and due any day) it WILL hide more than any shirt could. I like the jackets that are a little longer and sit on my hips, hides even more! I haven't seen anyone at a rated show wear a western shirt, but occasionally do at open shows. If you are going to wear a western type shirt at a open show, you want one that fits perfect, not bulky looking. A bigger shirt doesn't hide more, it does the opposite and make us look more "frumpy" lol. Also, be sure to iron and starch it. It defiantly needs to be tucked in, no way around that. I would also add a belt that matches your pants. Very plain, with a plain buckle. Again, this will not emphasize having an extra bulge, it will actually make you look smaller, I promise. The same with show pants or jeans, starched, and fitted, if they crease at your knee and shoe, have them hemmed. On the local open horse shows in halter you might see someone in black jeans and a western shirt, but thats really unheard of at breed shows. I show both, and before minis showed big horses for maybe 8 years? I have different clothes for both types of show.
If your going to wear a hat, it needs to be a very good quality felt hat. The number of X's corresponds with how much fiber is in the felt. a hat with low X's is a cheaply made hat, and will look cheap, and not hold its shape. Get the best quality you can afford. Rods western wear used to sell good quality hats for a great price. I think mine was around $100, and I take it to AQHA congress with me every year where they shape and clean it for free because I bought it there. The fit and shape of a western hat can make or break you. I usually have to get about 1/2" of brim trimmed from my hats so they dont look too big on my head, it makes a world of difference. I also get the squared off quarter horse crease, it's whats "in" in the show ring if your wearing a western hat. Make sure your hat fits correctly, you want it to sit about 1/2" above your eyebrows, no more because it will look like a clown hat thats too small, and no bigger because it will fall in your eyes (or off when you trot) Keep it in a hat can so it keeps its shape.
Move the show halter up maybe 2 holes on your pinto, you want it sitting about a thumbs width below the cheek bones, at the most, or it will make their face look long and out of proportion. Also, if their mane does not want to stay all to one side, you can use a "slinky" hood or mane tamer that will train their mane to stay all on one side, then right before you go in the ring, you can put a little clear gel or hair dressing on their mane to make it look smooth, and lay flat. I prefer manes on the right of the horse, but thats a personal preference.
Your appy is beautiful, but that nylon halter is really overwhelming on its small face. a nice fitted show halter would make a world of difference. Depending on size, the one you have for your pinto might fit, and the blue would look nice on your appy. If they dont show in the same class, could you swap it out between classes? Would save you a few bucks if you didnt have money to invest in an extra halter right away.
I agree on thinning the mane and forelock on your appy, they also overwhelm how small it is. just take your clippers on the underside of the mane, and clip maybe 1/2" wide path lengthwise up the neck, to remove 1/2" of mane at a time. After you do 1/2", stand back and take a look. does it look thin enough? You can always do another path, but you cant glue it back lol. My horse has over 1" clipped off, he just has a really thick mane. on the forelock, clip the underside into a V, by cutting into it on a diagonal so the V left points towards the horses nose. This will thin it out, and you will be able to see your horses face much better. Then, the gel before going in the ring will keep in in place and tidy.
I would use hoofpolish on both horses. Always use clear on an appy, so you can see the hoofs. Most appys have striped hoofs, and they should be seen. On the pinto you could go either way because he has white legs, but I prefer black on everything that isnt an appy. Try both and see what looks best.
Wow, seems like a lot to swallow huh? It's really all pretty simply, and once you do it, it becomes second nature.