Saving Vector settings per game with lr-mame

[nicktf]

Pi: 4; default canakit psu; Retropie v4.7.18 from RP website; keyboard, Atari Fightstick;

Hi! I have an arcade romset based on the excellent spreadsheet from Roslof, and I'm using lr-mame (1.8.8 or 0.232) for vector games. I have found settings I like, but I cannot for the life of me save some of them. I'm working with asteroids right now.

I'm changing the settings from the Mame menu accessed by "TAB" during the game. On the "sliders" menu, I can change brightness, contrast and gamma, and this setting sticks - it gets written to ./roms/arcade/mame/cfg/asteroid.cfg

<?xml version="1.0"?>
<!-- This file is autogenerated; comments and unknown tags will be stripped -->
<mameconfig version="10">
    <system name="asteroid">
        <video>
            <screen index="0" brightness="0.960000" contrast="1.550000" gamma="2.000000" />
        </video>

If I change any of the other slider controls, nothing gets written to this file and the changes are lost on restart. I particularly want to change flicker and dot size. If I try and write my best guess into this file, it just gets wiped.

If I run Mame64.exe on a PC, I can see that changes get written to vector.ini

#
# CORE VECTOR OPTIONS
#
beam_width_min            1.00
beam_width_max            4.00
beam_intensity_weight     0.75
flicker  

Looking at these changes, it seems that retroarch-core-options.cfg would be a good place to store them, and I can see that the settings exist for prior versions of mame, such as Mame2003.

for example - here you can see where I added them compared with mame2003

mame2003_vector_flicker = "20"
mame2003_vector_intensity = "1.5"
mame2003_vector_resolution = "1024x768"
mame2003_vector_translucency = "enabled"
mame_beam_intensity_weight = "0.75"
mame_beam_width_max = "4.00"
mame_beam_width_min = "1.00"

This has no effect

I also tried adding vector

mame2003_vector_translucency = "enabled"
mame_vector_beam_intensity_weight = "0.75"
mame_vector_beam_width_max = "4.00"

Again, no effect.

I tried adding them to /configs/all/retroarch/config/MAME/asteroid.cfg - again, no effect. I also notice that with Retroarch, doing an Override => "Save Game override" wipes this file out.

I also tried adding them to /roms/arcade/asteroid.zip.cfg - no joy.

What am I missing? I'm sure it's me.