If you could run different spectrums for first vs second half of flower, what would they be?

I have two 4x4 flower tents.

If it's beneficial I can run different spectrums in each tent.

First half of flower: 3500k or 4000k

Second half of flower: 3000k w/ uvb

Good idea or am I just splitting hairs?

tia

I think it's basically splitting hairs. Someone correct me if I'm wrong but if you went from say 4000k down to 3000k you'll get more red but you'll also lose overall light output. In other words you might as well just keep either in the entire time because they somewhat balance out.

I don't think anyone here truly knows which is better for flowering.

In my latest setup I aim for a base light of 3500k. After the initial flowering stretch is done (2-3 weeks after flip) I add in a flowering booster bar, which has deep reds + UVA + actinic blues + far red at dusk\dawn.

Many farmers that use hps will switch to mh in the late stages to boost trichs and resin. Modern white LEDs have a wonderful full spectrum that includes plenty of blues in all k-ratings. The way I go perpetual, this is mute. I hav flowered from 2000k to 4000k and been very pleased. My favorite is about 3500k led light. The vero and Cree chips have it all.

Vero @ 4000K and the CXB chips @ 3500K seems to be preferred for those who don't switch light between veg/flower