I think I have most of it taken care of in the attached ini but the starting grid is sort of a compromise, depends on how much you like the current sf-line placement lol.
Apparently the pace car will enter pits the first time it can and with the way sf-line and pits are placed here it means it'll enter earlier than wanted. I moved the grid 200 meters down the road so it's after PC's entry to pit road point and it seems to have worked.
Another option would be to move sf line. You wouldn't have to redo the track, if you right-click in a segment one of the options is Make Lead Segment. In this case neither of the 2 straights parallell to the pit road would make for a "natural" sf line though so you'd have to split the one you choose. If you do, do NOT Unlock All Geometry before you split because that will be a terrible mess with heights. Moving sf line would also mean having to change literally every single dlong value in the ini lol
The AI seems to handle waiting for the pace car to enter pit road better than I expected though so you might be able to keep it where it is.
One thing you should change though is the pit road/pit stall surface definition I've marked in my pic. Cars can easily end up there since there is no wall inbetween and any car ending up there will get a "You didn't enter the pits safely" penalty. Just change any surface definitions that are either Pit Road or Pit Stall to Apron and it's fine. If you want to be sure you've changed them all go to View/Display Extended Surface Types to see if you've missed one. There are no pit stalls there anyway so no reason not to change it.
Do some test races to see if everything works as expected. I didn't race myself, just watching AI and I might have missed something.