Unlike Highlander, there is not a "There can only be One."
This is a time of tough sledding at the LGS, too, as around 4-6 million other people all also made the same decision you did. So, there may be far more variety at the rental range than the LGS.
T-shirt carry is its own thing altogether. For one, you may need a size larger than you currently wear (or to go to Duluth or the like and get "long-tailed" T's). IWB with the belt over often can "smoosh" the best--but, you need to wear trousers that will take a belt (and five belt loops are better than 7 for spacing the "where" on your belt, too).
It's worth getting some one else to eyeball just now concealed you are.
And, everyone's mileage varies at this.