The change I added simply throttles the mining (it just slows down sending work) if it exceeds the bitmain_overheat and keeps doing that until it gets back to bitmain_temp

To use it, you'll have to edit /etc/init.d/cgminer and add the options in there.
Yeah it's rather odd how they simply disabled the extra options when they copied the luci code from avalon.

I have had to modify /etc/init.d/cgminer on my ants as well since they actually messed it up - it runs cgminer twice in that script, first time directly and 2nd time properly
You can see the two times:
1)
 $APP --lowmem --bitmain-options 115200:32:8:$_T0:$_cf:$_regv -q >/dev/null 2>&1

2)
 start-stop-daemon -S -x $APP -p $PID_FILE -m -b -- $PARAMS

You're best to comment out the first one (put a # in front of it) then edit the:
 PARAMS=" --lowmem $AOPTIONS $POOL1 $POOL2 $POOL3 $_pb --api-allow $_aa --api-listen"
and add your options on the end


.... HOWEVER ... these is a way you can hack options into that line using the luci web interface
If you add them on the end of a pool password:
e.g. say your pool1 password is "x" then in the luci web interface you can set it to:
"x --bitmain-temp 50 --bitmain-cutoff 60"

I used this to set the --api-description e.g. set pool1 password to:
"x --api-description Ant90"

i.e. you can use this hack in the luci web interface to add any cgminer options - on any version of the ant with any cgminer binary.