I have been wondering the exact same thing as you, so I'll give you the run down from what I have learned in the past few weeks. This may be a bit long winded, but I hope it helps.
I have a Ruger GP-100 with a 3" barrel, and also a new SP-101 DAO with a 2.25" barrel. I have had this GP-100 for about 3 years and I like it very much. It was a South American police import that I got from Centerfire Arms for about $270 shipped. It still locks up nice and tight.
Fast forward to me getting my CHL a month ago. I was leaning towards the SP-101 for carry, so I picked one up from McBride's here in Austin. They had a great deal on them, $415 or so. I figured its smaller frame would be a plus for concealed carry and I loved the idea of using .357 mag in my CCW. I'm 6' 0" and weight 230. I usually dress exactly as you described, some sort of t-shirt or light dress shirt and cargo shorts.
The SP-101 didn't work out badly, but using it didn't turn out as perfectly as I wanted it to. First, I bought three different holsters for it. First, I tried
this Blade Tech IWB. The belt loops on the holster protrude too far laterally under shirts and it bulged like a 30 pound tumor on my belt line. It was scrapped.
The next holster I tried was a Bianchi Nemesis pocket holster. I heard all the talk about how SP-101s were too heavy to carry in your pocket, but I thought I could handle it. I found that with most of my shorts, as long as my shirt would cover the pocket opening, then pocket carry worked fine with the SP-101. It's a little heavy, sure, but I'm a big guy and I can handle it. In my Dockers slacks that I wear for work, I will have to forgo pocket carry for IWB, however. The Dockers pockets just aren't big enough, I found.
The third holster I tried with the SP-101 was
this Hoffner's holster. It carries high and outside the waistband, which is nice. It works very well and prints less than a normal Kydex IWB holster, I found. It works well for me, but I can't say it's 100% effective for CCW. You definitely need to wear a favorable shirt in order for it not to print. I found it to conceal more readily in the 1:00-2:00 position, but I couldn't sit down. I had to put it in the 2:30-3:00 position in order to be able to sit down, but if you looked, you would probably notice the bulge. I decided at the end of the day however, that if you saw the bulge, that you would probably not know what it was and it was not a cause for concern. I came to this conclusion after asking my girlfriend (who isn't that gun savvy) to find my CCW on me. She was unable to find it every time and when she did find it, she said she didn't know it was there at first.
I still use my SP-101 for CCW, and I confidently use either the Bianchi pocket holster (which is easier to use and gets used more often) or the Hopffners IWB.
I went shooting on July 4th with my girlfriend and we took the SP-101 with us. I had never shot full magnum rounds in an SP-101 before, and I have to admit, that is a healthy amount of recoil. I'm going to get some Hogue grips. It is incredibly accurate for such a short barrel.
But in my search, I found another handgun that will be my primary CCW. Someone in Austin just yesterday was selling a Sig P239 in 357 Sig. It had the box, 4 mags, papers, Hogue grips and a Don Hume leather clip IWB holster. Let me tell you, in this Don Hume holster, it absolutely disappears. I don't carry it IWB, but more like inside the belt loop and outside the pants. I can wear it at 3:00 and my girlfriend can't see it at all (and I can sit down comfortably, yay!). It is about 1.1" or 1.2" wide, and the SP-101 is about 1.5" wide, so it makes sense that it bulges a little less.
I have a Sig 229 in 40S&W and Browning Hi-Power in 9mm, in addition to what was mentioned above, so this sheds some light on what I decided was a better carry tool versus others. I haven't tried to carry my Ruger GP-100 yet. I imagine if you found the right holster it would perform excellently, of course, but I don't know of any yet. My GP-100 stays on guard duty on my side of the bed and hasn't moved from that spot except for range practice.
I hope this helps. If you try different holsters, please post your thoughts here because I'm still learning myself and any info would be useful.