Flowering under 13-14 hours daylight

Hi, I live the canaries (28 degrees north) and the daylight hours never exceed 13.8 hours throughout the summer.
March 1st, daylight hours = 11.5
April 1st, daylight hours = 12.3
May 1st, daylight hours = 13.1
June 1st, daylight hours = 13.7

I have a bunch of plants veging under a couple of 600's for now (20/4), the biggest are working on their 7th node. In the next couple of weeks or so I expect the sunshine to really come out and so will be moving some plants outside. I need to get a quick harvest in, solely making use of the natural sunlight. My plan is maybe to grow about 7 of the girls up indoors (taking outdoors when it's sunny) for about 2-3 more weeks and then move them outside into their grow holes/bags. So lets say that would be the beginning of April.

Basically my question is, at what point over the next few months will daylight hours be getting too long for flowering? I don't particularly want to have to bring them into the dark each evening, but want a small harvest by early June. I have some nice Church X Critical+ plants (8 week flowerers).

Any comments would be appreciated.

I'm jealous. How's island life? Anyhow, I think you are going to have tough time keeping them from reverting or going hermie.... what's the outside temps? I really think it is a crapshoot... some plants show pre flowers flower when sexually mature under 18-6... I've grown crit+ but I don't remember how sensitive it was to light. Personally I would go 16-8 this week, 12-12 next week and then throw them outside and cross my fingers. worst case you bring them back inside to flower. well worst-worst case they hermie ... good luck.
SC

thanks for the info. The lowest temp is 12 at night and up to 20 in the day. Island life is slow as ever, I out in the middle of nowhere. Any thoughts on putting them in the dark for 36 hours before putting them outside to help kick off the flowering process? Whatever, I'll make sure they are in easily movable containers so I can bring them in each night if necessary.