pi2Scart Video center

[siocone]

hi, i have the pi3b+ running with pi2scart.
i use a small phillips tv in a homemade arcade cap.

to my question when i play mame strate the picture is not centered. I found two ways to set something but the system does not save it per game.

once in the menu of recalbox under CRT I can move the picture to the left and right and enlarge and reduce the height I can only move it.

in the retroarch menue under video I can adjust the image in all variants but only as it was previously defined in recalbox. (I think at least) so I have a scratched bar at the top and bottom that I can't get rid of, so the image can only be adjusted within. (no pal bar)
and the picture is way too wide... but that lets you adjust easily. only every time I want to save the settings and reload everything is reset.

can someone help me?