I have the supertuck with a 5.11 gun belt and also the 5.11 holster shirt.
I can't say the supertuck makes me feel comfortable. even with the gun belt (very recommended by the way) it's not that comfortable and there is a bump sticking out where your gun meets your "love handle"
the holster shirt is nice however you need to get used to it being so tight on your body and there is the whole "how fast you can draw" issue.
I don't believe it's a good solution for the hot days the shirt materials ain't that "breathing" if you know what I mean.
I wish I could tell you about a good solution but i don't have one.
I guess I hope I'll pick up something from this thread...