I carry A G-30SF in Cross Breed Supertuck, or A RM lowrider. And I just bought A silent thunde from A member here.
The 30 is thick and it does take gittiing used to. I would first recomend A good belt to start with, (that will make A big difference) in carry for the 30.
All the above conceal good enough under A t-shirt. I do use A 9 rnd mag though.
Im 5'7" and around 210 if that helps. Good Luck
I carry a G30 in an MTAC with a standard non-gun belt. At 4-5 o'clock is conceals fine under a polo shirt and I can sit in my car with it comfortably. That said, a G36 would be much easier to conceal, but I'm ok with what I've got.
I plan on getting the kydex body for my 1911 on the MTAC so I can try it out, too.
I've been carrying the G30 regularly lately. It is noticable bulkier than my HK USPc or G27. I use a Mitch Rosen belt. I have two different IWB holsters. A Comp-Tac Infidel and Garrity Inconspicuous. The first is kydex, faster on the draw and easier reholstering. The second is leather and is much more comfortable.
I carried the G-30 several times in a Crossbreed IWB holster. When you have lighter weight, thinner carry guns, it makes it difficult to choose the 30. So, I put a Crimson Trace laser on it and remanded it to nightstand duty.