I'm sorry but there are so many dumb answers in this thread. Retuning your bass also does things to its intonation. It does things to the timbre. It does things to how it sounds in your ear. If you want to train muscle memory, that's fine. But to so on a well-tuned, intonated bass in A=440. Don't retune your bass, pitch shift the song. You want the intonation of your bass and the response to be the exact same time every time you play it, not depending on the song.
True if we were talking about going down to D G C F or up to F# B E A. But between A=435, A=440 and A=442 those things really don't come in to play. Most people can't even hear ±5 cents and the average fretless player probably can't manage better that ±10 cents - from what I hear most don't even get close to that. The difference between 440Hz and 442Hz is about 8 cents - enough to beat or sound 'sour' but not enough to affect the physical response of an electric bass.