Thank you for reaching out and for showing interest in us and our lamps.
Most plants both want and need a high intensity of light throughout their flowering phase. They will survive if given too little light but they will stretch a lot and you will get a plant that isn't good looking and well being. It will show in the harvest as weak looking instead of big and dense buds.
To simplify everything and say it as it is, our Z2 model is crafted for small grow tents and closet grows. It covers an area that is just slightly larger than 1'x1' with adequate intensity for flowering. There will be light outside of that area but it will not be high intensity that is required during the flowering phase. Our Z5 lamp model covers an area that is 2'x2' with high intensity. We have measured it inside a 3'x3' and this also showed that one Z5 does not cover this tent fully. The same goes for two Z2 working together inside a 3'x3' tent.
So this all comes down to what size your plants are and how large you expect them to finally become. If they are 1.5'x1.5' wide, you will do very well with one Z2 per plant. If they are larger, I would recommend the larger lamp model.
We have experimented and tested ourselves to grow a little more than we should (multiple large plants per tent) with both of our lamps. They were tested at the same time in 3'x3' tents next to each other. Our Z2 draws 50 watts and our Z5 draws 112 watts. Both tents had the exact same conditions except for the lamp used. The tent with the Z5 had twice the yield compared to the tent with Z2 in it. Yield is directly tied to light intensity (up to a certain point). If you have plants that are bigger than what the Z2 can cover, I advise you to consider two Z5's instead, if you want your plants to live up to their full potential.
I just want to make sure that you are fully informed of the different options and outcomes. What intensity you achieve at certain heights and how far the intensity reaches on each height is measured in PPFD (umol/m2/s). You may have known all about this already so I won't dive too deep into this.
Working your way towards a height of 1' above plant canopy will result in a center PPFD value of around 900 PPFD, with both of our lamps. This is the maximum level of light that we recommend and only in the late stage of flowering. If your plants are 2'x2', The Z5 will cover them nicely when we average out the values and with a minimum level of 300 PPFD covering your outer edges.
Our intensity maps can be found in the link below for both our Z2 and Z5 LED grow lights.
They give a clear picture of how they perform at certain heights and how big an area they cover. Keep in mind, two lamps hung next to each other will benefit from overlapping light footprints and weak areas will get increased intensity. If you are interested, I can hang and measure two Z2s inside a 36x36x80 tent this weekend to give you an exact picture of what to expect from this option.
Sorry for the long answer. I am mentioning all of this as I suspect that your plants are quite large if they have been grown outdoors all season. The last thing I want is for you to realize all of this on your own in the late stage of flowering.
Let me know if something was unclear or confusing and I will do my best to fill in.
Hope to hear from you soon.