Moving out to in during flowering advice

I have a few girls that has been growing outdoors in 5 gallon pots since mid-May. All are clones and with exception of the Super Silver Haze the girls are around ~3 feet tall. The SSH are almost 6 feet tall and the other girls are GDP, OG Kush and Hindu Kush Skunk. The SSH are barely showing preflowers whereas the rest are ~3 weeks into flowering.

Due to possible security reasons I will need to move them indoor ASAP. Luckily I just finished my indoor setup which is running with a Sunlight Supply 600watt HPS. What type of shock/stress can I expect from moving them and, if possible, please advise on the best way to make the transfer as stress free as possible for my girls. Thank you Braddahs and Sistahs!

turn the lights off at dusk and back on at dawn so u dont mess up the photoperiod. i really doubt its gonna hurt your plant to switch, they wont get as much light from the hps so growth will not be quite so fast.

You will bring in bugs so be prepared for that.

darkdestruction420, that is a good point and I think will be a problem for me as I am actually planning on reversing the photoperiod. I want to run the lights at night and have them off during the day. Two main reasons for that is it will be cheaper to run my lights at night and also my intake for ventilation (both intake and vent are active) is coming from the outside and it will hopefully make temperature control a little easier. I wonder if I give them a 24~48 hour dark period and then introduce my planned photoperiod if that will work? Or at least reduce the shock?

Illegal Smile, oh man, I have been dealing with minor mite issue which I have been able to take care of (so far). I would no doubt be bringing these pests (among others) inside my indoor but I think I would rather deal with this instead of a possible security breach. I do plan on bombing the area after this grow though. I'm already reading/search up on how to bomb/cleanse the grow area on RIU....

Thank you for the replies! Please keep them coming!

switching photoperiod isnt too big a deal yet hopefully, it may shock em a lil bit but i dont think it will hermie them, but its still a possibility none the less.