I am bumping to see if anyone has anymore input.
As far as sizing for english saddles is it the same as western?
Nope, sizing is a little different for the rider. For English, measure from the center of the cantle down to one of the rivets on the side of the pommel (it doesn't matter which side). That measurement is the rider's size. As a general
rule, the English saddle will measure about 2 inches bigger than your current western saddle to be comparable. Still, sit in it if possible and make sure that it is comfortable in that size. A tack store employee can probably help you somewhat with finding your size if you need help.
As far as brown vs. black tack, unless you're showing it doesn't matter what color, purely personal preference. Unless you're showing dressage, brown is definitely preferred. Probably the most standard color of brown tack is havana, and that color is fairly easy to match even across brands. Oakbark is pretty common, too, and is a brighter shade of brown.
Pads: Again, if you're not showing, its up to you. If you are showing, there are some unspoken "rules". In the jumper ring, a square cut pad is fine, even with some color depending on the size of the show. In the hunter ring, even on the flat, you want a shaped white pad, either sheepskin or faux sheepskin. I like the synthetic to show with just because it's whiter. The off-white of the real stuff contrasts too much with all my guy's white, and something always looks dirty
. I wouldn't put 2 pads on at once, no matter what the cut. That can mess with the fit of the saddle, and you run into the same kinds of problems as overpadding a western saddle. It's kind of a fad to over pad right now, at least in my area. Makes me cringe to see people riding with a western blanket under a schooling pad under a shaped pad under a saddle.