#1
Ok, I play older metal (Death, Metallica, Megadeth, Slayer, Morbid Angel, etc.) but I'm usually in E standard tuning. Recently I've started tuning a whole step down to D standard because of my love for the band Death. How does this effect tone, strings, picks etc.?

1.) What gauge strings do I need to play in D standard so they're not all floppy

2.) Do I need thicker picks while downtuned?

3.) Does downtuning effect tone? Do I need to resetup my EQ for my new tuning?
#3
1) I would definitely suggest 10 or 11 gauge strings.

2) You might as well. I suggest Jazz III Dunlops.

3) Depends, you may have to tool around.
#4
You definitely shouldn't need thicker picks because bass players often use similar gauge picks to guitarists, such as me for example (dunlop .73mm).

EDIT: I play bass btw