240p Svideo Still hurting my eyes on my old CRT

[Mazon]

Hello everyone,
English's not my main language, and i'm quite the newbe so i'll try my best, sorry in advance.

i finally decided to create a new thread for my issue as i feel that i'm close to giving up now (even if i've made great progress thanks to those forums).

The idea is pretty common i guess, i bought a Pi3 and an old and small CRT TV for 10 bucks and i wanted to use Retropie on it.
I started with an HDMI adapter and since then the 4.2 came out, with the official 240p outpout using the Svideo I'm using this method.
And even if since i started everything (i never use a raspberry, first time and still learning) i see some progress (it was a flickering mess with now way to read anything at start) i still quite can't play more than 10 to 15 minutes, my eyes are hurting quite fast. The colors are too saturated (even with adjusting the TV setting) and i can see some scanlines, yet not that much and overall it's to clean and bright, it hurts. (FYI i just tried NES/Genesis/SNES and Ps1 emulation, i'm not yet into MAME and NeoGeo).

i'm starting to feel i'm gonna get back on a hdmi screen... Which is a shame.

So here's my config :
I'm using a jack to Svideo/rca converter (https://www.amazon.fr/gp/product/B003OSU5WS/ref=oh_aui_detailpage_o00_s00?ie=UTF8&psc=1) which works pretty well and i plug this into a scart converter.

I put this code into the config.txt file :

uncomment for composite PAL

#sdtv_mode=2
#sdtv_mode=16 # progressive NTSC
#sdtv_mode=0x10 # progressive NTSC (using hex notation)
sdtv_mode=18 # progressive PAL (this is a french TV, so PAL is used)
#sdtv_mode=0x12 # progressive PAL (using hex notation)

disable_overscan=1
framebuffer_width=320
framebuffer_height=240
scaling_kernel=8
overscan_scale=1
disable_audio_dither=1

No idea what those last 3 does but some user on this forum use it so...

Now if i get it right, the output is correct yet the emulator is sending a high resolution (not 240p) but every changes i try on the retropie menu doesn't change much ( i did put save on exit ON).
Apparently some users have a core config for each emulator but i don't know where should i enter those code (i'm referring to some advices in this thread (https://github.com/raspberrypi/firmware/issues/683#issuecomment-283179792).
When i'm using the select+y shorcut in game, i don't see every option people are referring to.

I'm sorry if i talking too much, i'm trying to be as clear as possible.

I don't want the purest experience with the perfect pixel and RGB colors but just to have a good old smooth CRT feel.

Any help would be greatly appreciated.