I carry a 3" 24 every day (14-20 hours straight)in a Black Hills Leather IWB paired with a Beltman belt. I usually have no problem concealing under a tshirt. Weight is no problem to me, a good belt and holster is key to stability. I cannot carry owb, it flashes the gun and even when covered makes me look like have an alien growing out of me.
I've found that any round butt 4" N is comfortable and easy to conceal (I am a bigger lad though).
I've never used a Kramer for an Nframe, but did use one with a 1911 and love their products. I think your n frame/kramer combo should be fine. Make sure you get a good pistol belt.