Long time lurker and have always appreciated reading content from this community, so I signed up.  I am wanting to put together an EDC handgun .  I have several I rotate through and have been partial to glock and the S&W shields currently owning a G43, Shield 9, Shield 9 2.0 and Shield 40 2.0.  None of them are optics ready and none have a light rail. 
Will carry IWB and in an eberlestock fanny pack.
I am assuming that tough and reliable are implied, Some other requirements:
1. Weight - I would like to keep it as light as possible knowing if it is a tank I am less likely to carry it.
2. Slim Profile - Thinking single stack. I have a G23 and G29 and never carry them.  Just too big and bulky and print easier. 
3. optics ready - i plan on mounting a red dot.
4. Light rail - plan on mounting a light
5. Capacity - I know if it is a single stack I am sacrificing capacity, but would love to get into double digit capacity.  10-12-15 etc.
Open to any suggestions - please shoot me your recommendations for gun, optics and lights!  Thanks in advance!