I've heard of people wearing the IWB holsters inside the belt, but outside the pants. That always struck me as counterproductive as you lose the main benefit of IWB, which is to hide the bulk of the gun inside your pants. I'll give it a try though. If it's more comfortable, I can deal with the reduced coverage. I tend to do the t-shirt and flannel in cooler weather as well, though I'm hoping to get IWB working so I can get by with a loose t-shirt in warm weather. NoVA summers are hot and humid.
Chris