Not an expert and I have questions posted here too, although I have dealt with the two issues you are asking about already:
-on the game resizing to fit the bezel - go to options/mame config/Basics - click on the config button to the right of the mame executable path. In the Mame.ini editor that comes up, go to display tab, and unclick bezel in the artwork options box in the lower left of the tab. you may have to change other settings - crop artwork, overlay - something to play around with.
-on scrolling X amount of games at a time or what i use, which is scrolling a letter at a time - go to options/controller/joystick/basic and assign shifted joystick directions to either X up/down or letter up/down drop boxes.
good luck.