I like button 1 on the bottom for 3 button or less games, however for these games I like to map:
1 2 3
1 2 3
x
if I'm using my seven button CP (a hotrodse). Since I have other CPs, I wired them "funny", but they go with this fine. For example, I have a rotary CP with "two" buttons mirrored on each side the the sticks (b b stick b b). If I used mame's defaults, it would go b5 --BINGO! Either that, or I was attempting to say "before" but it was too many letters to type-- stick b1 b2, but with the same remap as above, that's b2 b1 stick b1 b2.

IMO, with mame's ease of remapping, the physical button wired layout is very different than the game button mapped layout.
For example, the physical wired layout could be:
q w e
a s d
z
the SF family game mapped layout:
1 2 3
4 5 6
-
the neogeo family game mapped layout:
- - -
2 3 4
1
and the 3 button and less games mapped layout (IMO the bottom is more important):
1 2 3
1 2 3
-
Also, I don't play SF type games much, so
if I cared about it, the physical wired layout should match the games I play (3 button & less) mapped layout to mame's default mapping. (But since I remap anyway, I don't care.) [/rant=off]

BTW, the ctrlr file is the way to mass remap.