So many variables to your decision but here's my experience. Note that this is on a 2009 Suzuki DL650 V-Strom - I won't have my Spyder for a few weeks yet. I mention that because airflow differences between the two machines could make things different.
I wore a 2003 Roadcrafter Classic (I bought it used) from 2009 through 2020. As a commuter, I think there was nothing better - it goes on over my work clothes. So easy. Also worked well for my annual trips with friends. Comfort wise, as long as I was moving I was fine in the heat. I really like the underarm vents.
I spent a year in a Cycle Gear Sedici mesh jacket that I had to buy while on a trip after a user zipper failure on the Roadcrafter (more my fault than the suit's). And I'm a believer in the concept that in really hot weather, a solid material is better than mesh. With the caveat that I'm on the Pacific coast and have only ridden as far east as CO, WY, MT so I can't speak to the humidity in the south and on the east coast.
While on the topic of mesh, I did look at motoport gear. Good stuff with a good reputation. But I couldn't get over the idea that I had to stop and add/remove a liner when dealing with rain. In my Stich gear, I don't have to worry about rain, i just get to keep going. Note on the one piece: on my older version, after really heavy or prolonged riding in the rain, a couple times I did experience the dreaded crotch leak due to the pooling of water in my lap. I don't know how much that issue has been resolved in recent years and with the newer waterproof zippers.
After hemming and hawing about what gear to get to replace the Roadcrafter, I finally decided to go with the Darien jacket and AD1 pants. I'm still breaking in the jacket and learning what adjustments I need to make at what temps. Discovered that the unlined Darien is very different than the lined Roadcrafter Classic. I've found a good windproof shell that makes up for that in cooler temps. In warmer temps, unlined seems to be better.
I'm an Aerostich fan, no doubt. As I get a chance to ride more this year (now retired) and finish breaking in the Darien (the AD1 pants were good from the start), I'll figure out if I like two pieces better than the one piece. But so far, I do.
The best thing you can do is watch for Aerostich pop up events in your area. They bring lots of sample gear for you to try on to help determine size and how it feels on your bike (or one of their demo bikes). Or head up to MN to the factory. For sure, get on their email list so you can get information and notices of sales. Such as this one in my inbox this morning:
Save 15% on all IN-STOCK suits, jackets, and pants! (In-stock garments are NOT Individually listed on the website.) Call 800-222-1994 for in-stock suit size information, availability, and to order!