I normally go directly after work because the gym is on my way home and I like to get it out of the way, I lose motivation if I go home first.
I like to change my pre's after each tub, I've found F=MA and Bullnox Endorush work well. I have a high tolerance to stims so a lot of pre's don't have much effect on me.
The old Jack3d didn't do much for me but it might have been because it was an old tub, I'm about to try Mesomorph 2.0 so I'll see if it's any good.