I find that bike shorts do make a difference in chafe.
As a Clyde Lite, I avoid the road bikie sprayed-on look. No lycra. It looks great on 18 yr old ecto-meso. That was 60 years back. There is more of me now and I enjoy a looser fit in clothing.
I like the HOSS cargo shorts. I can get them in XXL (40 waist) from Price Point. In fact, just got another set. Since the shorts with chamois is the underwear, take a tip from the wife - panty liners. They work just fine.
I find the wicking shirts work and I scout Ross Dress for Less for golf shirts. I have a number of their wicking golf polos and they work great. Normal price was around $8.
Another item that works well is a reflective safety shirt, long or short sleeve. I get mine from SafetyDepot.com. They run about $13.
I have a Pearl Iz. long sleeve jersey that I wear as a windbreaker. On cold days (in So Cal) it's a Patagonia caprilene pull over, lime green Pearl jersery over, and if more is needed, a light windbreaker from NorthFace. Got that at their factory outlet at the Woodburn Exit in Oregon (no sales tax).