no i didn't try lzma or zst, i believe the ratio would be worst maybe you will get 8.10g to 8.15g...
from past experience the best setting for lzma i recommend lzma:a1:mfbt4:d512m:fb273:mc10000:lc8 or if you have alot of ram you could increase d512m to 756m or 1024mb still better than lzma2 or lzma:ultra that used by panker...
just be sure that you using fazip 64 for lzma to overcome memory limit in freearc.
the max lzma is d182mb in freearc alone without fazip...
[External compressor:lzma,delta,exe,mm,rep,tor,4x4]
header = 0
packcmd = fazip -i0 compress:{compressor}{
ption} <stdin> <stdout>
* srep need less tan 1gb decompresion memory for Assetto...
i will try to use pzlib:max:c64m+srep:m5f:a2+delta+lzma:a1:mfbt4:d51 2m:fb273:mc10000:lc8
no need for more than 64m for pzlib...