I never buy millet. Messy, wasteful and bring in the unwanted gird species!
Mainly I do black oil sunflower seed mixed with shelled and whole peanuts and maybe some dried fruit pieces if I’m ‘rich’ that month, LOL!
And homemade suet, but I have lots of access to animal fat/lard to use up. ;)
I buy a premium mix at Menards. It has oil and striped sunflower, safflower, nuts and a few other things I can’t think of right now. No millet. It’s pricey but I use my Menards rewards for bird seed. If I had the animal fat you have I would make my own suet cakes too. Used to a long time ago but suet is expensive now.