The Galco Summer Comfort is not a bad choice, but the lack of sweat shield is a legitimate concern if you don't have something between the pistol and your skin. That's why I switched from a Kramer #3 IWB to a BladeTech IWB. The latter has the sweat shield, the former does not. I carried a Glock 19 for years in the Kramer and sweat all over the last ½ inch of slide. That side of the slide acquired some curious pitting along the way well before I switched to the BladeTech. Seems silly, then, to choose a holster that doesn't offer a useful feature – at least for the way I was carrying. Guess I'm a slow learner...
I'm roughly your size (a little over 6 feet tall, 170lbs), and typically carry the Glock under an untucked t-shirt at aboutish 5:00 (right-hander). I used to carry a Ruger P90 the same way, too. As far as I know, no one ever noticed either one.
Where you put the holster on your belt is up to you when it comes to comfort and concealability. On the hip makes for a faster draw than behind it, but wearing the holster just behind the hip (as in 4:00) makes it more concealable and, in the case of IWB, more comfortable. At least it certainly works out that way for me. If, however, you spend a lot of time sitting, you'll likely be better off with the holster closer to your hip instead of farther behind it, otherwise you'll end up with the back of your chair pressing the gun into your back. Get a good gun belt. It'll support the weight of the pistol, and anything else you may hitch on it, far better than ordinary belts.
You'll likely find OWB holsters more comfortable than IWB and, yes, you can conceal almost as well with one of those as with IWB, the primary difference being that you'll need a slightly longer shirt. Raising your arms over your head, for instance, will cause your shirt to ride up, exposing in some cases the portion of your OWB that would remain hidden were the holster IWB.
Like many, you'll probably try a few different holsters before settling on one. Seems I went through six (two OWB styles and four IWB) before discovering what I really liked. As kayak-man mentioned, experimenting with a few cheapie holsters before spending more may be a good idea.
I've used the search function, but not much relates to both IWB and using only a t-shirt as the cover garment. Does anyone else IWB a gun this size without a heavier garment? For that matter, is there an OWB holster that will do this?
