CFL question

I am currently using a mixture of 6500k and 2700k mostly 2700k as I am in flowering mode.

My question is whats up with these 4100k lights im seeing and can they be useful as I have read mixed reviews cause the ones I can get in that Kalvin are 200watts.

So yes or no to getting the 4100k 200 watt CFL's

Well, is that 200W equiv or for real? Do you have a link to the lights in question? (or make model).
The temperature rating (Kelvin) of CFL's is a loose representation of the lights look, being cool or warm etc. It is not a good representation of the actual spectral output of the light. PAR and LED lighting systems allow you to home in on specific light frequencies that are useful to the plant. Getting a spectral distribution chart for your lights in question will tell you how well they will perform from the plants photosynthetic perspective. Tuning CFL's is hard to do (there are a bunch of us experimenting with various plans and equipment). The real downside is with CFL's that have big gaps in their spectrum or where too much of the lamp power is going into one frequency range like green, which is more or less useless to the plant. Lumens, Spectrum output and $/watts should be your initial purchasing criteria. Use the Kelvin rating as a very general guideline for red versus blue light only.

i hear between 5000k-6500K and 2700k only.. anything in between that, doesn't give the spectrum that the plant responds to.. so 4100k is useless pretty much

Thats impossible to tell just from the colour temperature, you need a spectral distribution chart for your lights to know exactly what is going on. 4100K is meaningless on its own.

BPM: there are a lot of different ways to skin a cat, and I think that holds true for lighting. The 4,100K light range might be a good mid-range lamp to add between vegging and flowering. Here's an example of what a friend who also uses T-5's suggested and I may try it on my next grow. He uses a massive T-5 fixture that either has eight or ten tubes and two on off switches. It's four feet long and it comes out of the box with half 6,500K blue grow lamps and half red 2,700K flowering lamps. Their selling point is that it gives your plants a more complete spectrum. The inclusion of your 4,100K's might make it even more complete.

He starts out with the brighter 6,500K blue grow lamps for vegging in all the receptacles. After about a month of vegging he starts swapping out the 6,500K's with red 2,700K flowering lamps. But he does it very gradually. This goes on for about ten days, with him removing the 6,500's and replacing them with 2,700's at one or two at a time. He claims that this gives his plants a very gradual light change as it occurs in nature. Eventually, they're all the 2,700K's for flowering. It makes sense to me but again the inclusion of your 4,100K's is something I'm going to bring up to him to see what he thinks. What do you guys think? HSA

If you want to talk T5's, spectrums and whatnot, you have to read this post.
https://www.rollitup.org/indoor-growing/358190-led-without-leds-my-first.html#post6576789