Shirts for a large target audience

My target market is mostly large people. Where I live, people tend to be not only quite tall, but also obese.

I'm targeting the families of kids in youth sports. The people like to wear the kind of shirts that advertise their kid is out there playing. They even tend to have the same shirt as a family, or in friend groups. So, I have some basic designs, but will also customize by putting names or numbers on the shirts, or the team roster (which is popular).

I personally like other brands better, but am choosing Gildan now for the following reasons:

1. Our area is almost 25% at the poverty line. Price does matter to many of these families.
2. As I said, we have a high population of large people, and I think the Gildan blend works with that body type and chemistry.
3. Almost every sporting store/print shop I've walked into is heavy on Gildan products, which tells me it's a preferred product in this area.

I am admittedly new to this area. The tee shirt/printing side of my business is growing out of requests. I have ordered shirts and printed materials for my clients from others, so I want to capture that money to grow my business. It's also another way to generate revenue during slower months, because my business is cyclical.

Yes, I know I have a lot to learn. It's been a few months now that I've been working on getting on equipment, deciding on a market, testing products, etc. So any comments will be helpful, even the negative feedback. Thank you in advance.