Hey, I just realized I never updated this thread. Just wanted you all to know that your good advice didn’t go to waste. 
Scotty’s first show was, overall, very good! Unfortunately, I don’t have any pictures. It was pouring down rain, so I was afraid to take out the camera. Anyway, it was a good experience. Scotty was very well-behaved; he did everything asked of him.
The weather was miserable: lots of cold, driving rain and a temperature of about 45 degrees (yay Minnesota). We were both soaked and shivering. We rode in a few under-saddle classes in the morning (got reserve champ, which sounds good, but there were only three in the division. :lol:), then took a quick lunch break.
The driving class was a few classes after the break, so I had a friend head Scotty for me while I put him to. She had a lead rope attached to him just in case, but he stood like a rock and was not impressed by any of the stuff blowing past him. She unclipped him and off we went. We headed off to the far corner of the parking field to warm up since the regular warm-up area was right next to the ring and I didn’t want to disrupt the saddle horses. It’s pretty rare for them to have driving classes here, so most of the saddle horses are not used to seeing carts.
As we drove off into the pelting rain, I very quickly realized WHY driving aprons became traditional – I was so much warmer in mine, even though it was only a single layer of thin fabric (homemade). I definitely see the benefit of an apron now. That thing was a lifesaver. My teeth stopped chattering once we got going a bit, but my hands were still frozen solid. I never thought to pack warm gloves for a show in August. 
Warm-up went well, but it was an early preview of the problem we were about to have in the ring: Scotty was fussy about the rain pelting in his face. He was perfect when he had his butt to the wind, but when we turned into the wind, he’d turn his head away from the rain and bob it up and down a bit.
When we got into the ring, it was the same story. He was perfect going away from the wind, but a little fussy going towards it. However, he still executed all of my commands obediently, and he was very nice and forward (he tends to be lazy at home). All in all, he made a good account of himself, aside from that minor issue. I was proud. 
We placed last out of three, which was no hardship because the other two horses were very good. I feel with a little more mileage, we will definitely be competitive on our local circut. Since that show I’ve noticed that the judges are pretty open-minded when it comes to the driving class, and they’ll place a flashier type if it does well. My friend placed at the championship show with her Hackney pony, so it’s definitely possible.
Learned that I definitely need to ride and drive in the rain more! Neither of us were used to it. :lol:
Thanks again for the tips!