There is a lot of info about red dots for carry in this thread:
http://smith-wessonforum.com/concealed-carry-self-defense/495516-red-dot-carry-gun.html
I gave my general opinion in post #18 in that thread.
In your case, I also have a couple of additional thoughts. How much shooting have you done with the red dot sight on your full size range gun? If you are not very familiar with the red dot yet, I recommend taking some time to get used to it. Try doing some quick close work from the holster with the red dot on your range gun. This training will give you a personal sense of the pros and cons of a red dot.
Also, if you do want a red dot for a defensive pistol, I recommend getting a top quality unit. The small red dots that I would trust for duty use start at around $500. If you choose a pistol with the slide cut for an optic, and add raised height suppressor sights that will co-witness through the optic, then the overall budget is nearly $1000 more than a base model carry pistol.
Good luck with your choice.