Wow, This will be a task. Either you can reduce your textures in size. - I am sure you are collecting a few by now. for segment textures.
For entity textures you can right click on the entity and under optional visuals, use the reduce texture value of 2.
In the setup.ini file
[GAMERUN]
realgameview=0
dynamiclighting=1
dynamicshadows=1
useeffects=1 <------ Could set this to 0
useeffectsonguns=1 <------ Could set this to 0
useeffectsonscene=1 <------ Could set this to 0
useeffectsonentities=1 <------ Could set this to 0
dividetexturesize=2 <------ I think this will use 0 or 2 or 4
controllerhint=0
vrmode=0
vrmodemag=100
mousesensitivity=100
producelogfiles=0
hsrmode=2
optimizemode=1
aspectratio=0
newblossershaders=1 <------ Could set this to 0
postprocessing=0 <------ Could set this to 0
showaioutlines=0
disablepeeking=0
[GAMEMAKE]
lightmapping=1
lightmapold=0
lightmapshadows=0
lightmapambientr=0
lightmapambientg=0
lightmapambientb=0
lightmapsunx=0
lightmapsuny=-1
lightmapsunz=0
lightmapsunr=0
lightmapsung=0
lightmapsunb=0
lightmapzerorange=100
lightmapatten=16
lightmapmaxsize=-1
lightmapboost=4
lightmaptexsize=512 <------ Could set this at 256 or 512, 1024
lightmapquality=15 <------ Could set this to a low number 5 - 20
lightmapblurmode=1
lightmapthreadmax=-1
bloodonfloor=0
imageblockmode=1
showalluniquetextures=0
systemmemorycapoff=0
entitytogglingoff=0
extracollisionbuilddisabled=1
alwaysconfirmsave=0
simplifiedcharacterediting=0
Make sure that FPSC creator is off when you change the setup.ini file. If you change something in buildgame, you will need to edit these settings again.
Hope this helps
Nothing but coffee in my veins