I have the Glock 19 and the Glock 43. Both are very nice firearms and both have their good points. I can carry the 19 like I carry the 43. The 43 is lighter and very easy to carry under your shirt, while the 19 is a little bit heavier you might need the XL shirt instead of the L shirt that day. Grip size is one of those "to each their own" things. I like both grips and shoot both well. The accuracy on both is very good with the 19 being a bit better imo. The magazine on my 43 does have the plus two and plus three extensions from T/Tactical. Depending on the size of your hand these feel good to me and control is better. I use a De Santis leather holster for my 19 which keeps it a bit closer to the body then my Black Hawk CQC level one retention holster. I will say the 43 does hides very nice and is light. So on those hot days or if you're running round, or playing with your trucks, working in the yard, fishing, etc. the weight and size wont be s problem.
Though if you want the 19 then get the 19, its a nice firearm and you'll still be able to carry it under your shirt. I've worked n played while wearing both, just the 19 every-now-n-then when I'm under my vehicles working on them gets to be pain when rolling round.