light cycle

i vegged some clones under 24 hours of light there outside now in socal and have been for 3 weeks and are flowering. the days are getting longer currently apr25th they get 13hrs 20 min my question is what is the maximum number of hours cannabis will continue to flower in? as they are pretty far along im hoping they just finish instead of re-vegging. by may29th they will get 14 hrs 15min the max they will get this summer will be around 14hrs 30min in may and june. another question does vegging under 24hrs effect there sensitivity to day/night cycles? does anyone have a definitive answer and does it vary based on strain some are indicas some are sativas? i assume shade does not count as dark because of ambient light levels as they dont get direct sun for the full photo period. sorry for all the questions im new to outdoor growing. im just concerned they may begin to re-veg right before they might finish as of now it seems there still flowering any help appreciated.

is there any chance you can put a box over them to make sure they only get 12 hours of light? or light proof bag.
i would say it would vary from strain on how sensitive.

i considered doing that. but on the hottest days 105-110+ i fear they would cook alive. i need to invest in a greenhouse with venting then maybe i could manipulate light easier.

any other input?