Regarding Atari Avalanche using Advance MAME in Retropie---
I tried all of the analog control settings and bumped them way up to like 100 paddle speed, 100 centering, and 200% sensitivity. The stop positions don't change.
UPDATE- Avalanche does work properly if you use a spinner (mouse) instead of the A-Pac (pots) such as the Turbo Twist 2.
The customization for that is in other threads but it is basically----
does require setting the mouse X values directly in the .rc config file so MAME reads the mouse properly-
hit f4, type sudo nano /opt/retropie/configs/mame-advmame/advmame.rc
device_raw_mousedev[0] /dev/input/mouse0
device_raw_mousedev[1] /dev/input/mouse1
device_raw_mousedev[2] /dev/input/mouse2
device_raw_mousetype[0] ps2
device_raw_mousetype[1] ps2
device_raw_mousetype[2] ps2
input_map[p1_dialx] mouse[0,x] mouse[1,x] mouse[2,x]
input_map[p1_paddlex] mouse[0,x] mouse[1,x] mouse[2,x]
input_map[p1_stickx] mouse[0,x] mouse[1,x] mouse[2,x]
Alt-X then Y to save the settings.
When in the game, use Tab and set the Analog Dec and Asc to an irrelevant key such as d or g on keyboard, to avoid spinner conflicts.