Question about lighting during Flowering

So my plant has been in harvest for a bit and I am guessing it only has 3-8 more weeks left. I am not doing it at my house so I cannot control the lighting well. Some times i get it at 12/12 exactly most of the time I don't , sometimes even leaving the light on/off for up to 2 days.
So far it doesn't seem like it affected it much cause it's growing nice, but didn't want to continue doing this because I think stressing the plant will reduce THC production. So I bought a timer but it only goes up to 8hours off / 8hours on. What is better? A regulated 8/8, or the previous setup which won't always be 12/12.

12/12 for flowering always and skipping days or not having it come on at the same time will greatly stress your plant man. Go and buy a new timer and you will thank me when your next harvest comes.

Yea buy a new timer, they're like $6-$10 at your local home depot or walmart etc.

hell buy two or three, Im glad i did.

What are the timers called so I can see the prices online?