Towards the bottom of the squat, or even closer to the start of the squat (when I use heavy weights), I don't really feel my lower back tight and arched. It's very annoying as I had to drop 60 pounds on the squat, and I still can't maintain a solid arch the whole movement. I can't even feel my low back tight at the bottom. Can you all feel your low back arched the full way through? Also, when I go up I think my lower back starts to round.
Considering a rounded back is the opposite of an arched back you probably need to work on your form. You can't round your back if you're sticking your chest out and pulling your shoulder blades back.
My question is when you squat, do you feel your lower back tight and arched the whole movement?
To answer your question, yes, I do feel my back tight and arched throughout the entire movement.
Honestly, if you're rounding your back at the bottom of a squat how we feel shouldn't be your main concern.
Wouldn't you prefer to correct this before you hurt yourself?