Update: Okay the following script works there was a pastebin copy paste 1 character problem.   
Ok well I have the script running on my server through deathmatch mode. Although there are still a bunch of models still visible around the map.     
This is the script: 
function removeObjects () 
for i = 550, 20000 do 
removeWorldModel ( i, 10000, 0, 0, 0 ) 
end 
end 
addEventHandler ( "onResourceStart", getResourceRootElement(getThisResource()), removeObjects ) 
I put that in  C:\Program Files (x86)\MTA San Andreas 1.3\server\mods\deathmatch\resources\[gamemodes]\[deathmatch]\deathmatch.zip       
inside a new file called removedefault.lua 
Then I opened the meta.xml in the deathmatch.zip resource and added   rite under  
Finally I set the gamemode to deathmatch and most things disappear when map loads    Now if only I can figure how to completely remove every single default model