I wonder what would be good/optimal settings in $NUMGRD if ORDER=4 is used for searching for conical intersections at the XMCQDPT2 level. I mean:
$NUMGRD ORDER=4 SPLINE=? CONFIT=?
Would this be reasonable:
$NUMGRD ORDER=4 SPLINE=4 CONFIT=1
which I took from an example in the manual where however ORDER=6 was used. I can't afford ORDER=6 and ORDER=2 doesn't seem to work good.