Wow Dude, those are some long sentences....:jointsmile:

Well, first off, welcome to cannacom.

"if there is anyway you can tell wether the plants will be m/f before the sexing shows, and when does the sexing show"

There is no sure way to tell, sex shows when days are getting shorter and the plants are sexually mature. That's gonna happen soon, but in a few weeks i think you will know for sure.
Stop using that slug killer. It's bad for you and the nature.
You can get rid of some slugs, if you clear away the grass/weeds around your plants....slugs don't really like open space...1-2 foot in diameter will be just fine...
You should get some good nutes for the plants. Find a hydro store or a grow shop, and buy some organic nute for cannabis....Like Fox Farm or BioBizz, BioCanna....It's not cheap, but the plants gonna thank you for it...

Peace....:hippy: